SkAdvancedTypefaceMetrics: abstract out linked list

+ use SkSinglyLinkedList<T>
+ move SkSinglyLinkedList.h to core
+ remove SkHackyAutoTDelete
+ getAdvanceData() -> setGlyphWidths()
+ finishRange no longer templated
+ remove unused templated functions

GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1953153004

Review-Url: https://codereview.chromium.org/1953153004

11 files changed, 195 insertions, 314 deletions

diff --git a/gyp/core.gypi b/gyp/core.gypi
index aeffa2b2d8..946aa33066 100644
--- a/gyp/core.gypi
+++ b/gyp/core.gypi
@@ -265,6 +265,7 @@
         '<(skia_src_path)/core/SkShader.cpp',
         '<(skia_src_path)/core/SkSharedMutex.cpp',
         '<(skia_src_path)/core/SkSharedMutex.h',
+        '<(skia_src_path)/core/SkSinglyLinkedList.h',
         '<(skia_src_path)/core/SkSmallAllocator.h',
         '<(skia_src_path)/core/SkSpanProcs.cpp',
         '<(skia_src_path)/core/SkSpecialImage.cpp',
diff --git a/gyp/pdf.gypi b/gyp/pdf.gypi
index 882c1e71db..ad6d66e17e 100644
--- a/gyp/pdf.gypi
+++ b/gyp/pdf.gypi
@@ -45,6 +45,5 @@
         '<(skia_src_path)/pdf/SkPDFTypes.h',
         '<(skia_src_path)/pdf/SkPDFUtils.cpp',
         '<(skia_src_path)/pdf/SkPDFUtils.h',
-        '<(skia_src_path)/pdf/SkSinglyLinkedList.h',
     ],
 }
diff --git a/src/core/SkAdvancedTypefaceMetrics.cpp b/src/core/SkAdvancedTypefaceMetrics.cpp
index 0e9ba95bf4..fab5f5e462 100644
--- a/src/core/SkAdvancedTypefaceMetrics.cpp
+++ b/src/core/SkAdvancedTypefaceMetrics.cpp
@@ -27,36 +27,13 @@ typedef struct FT_FaceRec_* FT_Face;
 #include <CoreFoundation/CoreFoundation.h>
 #endif
 
-template <typename Data>
-static void unwind(SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* ptr) {
-    while (ptr) {
-        SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* next = ptr->fNext.release();
-        delete ptr;
-        ptr = next;
-    }
-}
-
-SkAdvancedTypefaceMetrics::~SkAdvancedTypefaceMetrics() {
-    // If the stacks are too deep we could get stack overflow,
-    // so we manually destruct the linked lists.
-    unwind(fGlyphWidths.release());
-    unwind(fVerticalMetrics.release());
-}
-
-namespace skia_advanced_typeface_metrics_utils {
+SkAdvancedTypefaceMetrics::~SkAdvancedTypefaceMetrics() {}
 
 const int16_t kInvalidAdvance = SK_MinS16;
 const int16_t kDontCareAdvance = SK_MinS16 + 1;
 
-template <typename Data>
-void stripUninterestingTrailingAdvancesFromRange(
-                                                 SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range) {
-    SkASSERT(false);
-}
-
-template <>
-void stripUninterestingTrailingAdvancesFromRange<int16_t>(
-                                                          SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>* range) {
+static void stripUninterestingTrailingAdvancesFromRange(
+        SkAdvancedTypefaceMetrics::WidthRange* range) {
     SkASSERT(range);
 
     int expectedAdvanceCount = range->fEndId - range->fStartId + 1;
@@ -74,31 +51,7 @@ void stripUninterestingTrailingAdvancesFromRange<int16_t>(
     }
 }
 
-template <typename Data>
-void resetRange(SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
-                int startId) {
-    range->fStartId = startId;
-    range->fAdvance.setCount(0);
-}
-
-template <typename Data, template<typename> class AutoTDelete>
-SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* appendRange(
-        AutoTDelete<SkAdvancedTypefaceMetrics::AdvanceMetric<Data> >* nextSlot,
-        int startId) {
-    nextSlot->reset(new SkAdvancedTypefaceMetrics::AdvanceMetric<Data>);
-    resetRange(nextSlot->get(), startId);
-    return nextSlot->get();
-}
-
-template <typename Data>
-void zeroWildcardsInRange(
-                          SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range) {
-    SkASSERT(false);
-}
-
-template <>
-void zeroWildcardsInRange<int16_t>(
-                                   SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>* range) {
+static void zeroWildcardsInRange(SkAdvancedTypefaceMetrics::WidthRange* range) {
     SkASSERT(range);
     if (range->fType != SkAdvancedTypefaceMetrics::WidthRange::kRange) {
         return;
@@ -113,22 +66,19 @@ void zeroWildcardsInRange<int16_t>(
     }
 }
 
-template <typename Data>
-void finishRange(
-        SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
+void SkAdvancedTypefaceMetrics::FinishRange(
+        SkAdvancedTypefaceMetrics::WidthRange* range,
         int endId,
-        typename SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::MetricType
-                type) {
+        SkAdvancedTypefaceMetrics::WidthRange::MetricType type) {
     range->fEndId = endId;
     range->fType = type;
     stripUninterestingTrailingAdvancesFromRange(range);
     int newLength;
-    if (type == SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::kRange) {
+    if (type == SkAdvancedTypefaceMetrics::WidthRange::kRange) {
         newLength = range->fEndId - range->fStartId + 1;
     } else {
         if (range->fEndId == range->fStartId) {
-            range->fType =
-                SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::kRange;
+            range->fType = SkAdvancedTypefaceMetrics::WidthRange::kRange;
         }
         newLength = 1;
     }
@@ -137,13 +87,13 @@ void finishRange(
     zeroWildcardsInRange(range);
 }
 
-template <typename Data, typename FontHandle>
-SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
+template <typename FontHandle>
+void SkAdvancedTypefaceMetrics::setGlyphWidths(
         FontHandle fontHandle,
         int num_glyphs,
         const uint32_t* subsetGlyphIDs,
         uint32_t subsetGlyphIDsLength,
-        bool (*getAdvance)(FontHandle fontHandle, int gId, Data* data)) {
+        bool (*getAdvance)(FontHandle fontHandle, int gId, int16_t* data)) {
     // Assuming that on average, the ASCII representation of an advance plus
     // a space is 8 characters and the ASCII representation of a glyph id is 3
     // characters, then the following cut offs for using different range types
@@ -159,10 +109,8 @@ SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
     //  d. Removing a leading 0/don't cares is a win because it is omitted
     //  e. Removing 2 repeating advances is a win
 
-    SkAutoTDelete<SkAdvancedTypefaceMetrics::AdvanceMetric<Data> > result;
-    SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* curRange;
-    SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* prevRange = nullptr;
-    Data lastAdvance = kInvalidAdvance;
+    WidthRange* prevRange = nullptr;
+    int16_t lastAdvance = kInvalidAdvance;
     int repeatedAdvances = 0;
     int wildCardsInRun = 0;
     int trailingWildCards = 0;
@@ -176,10 +124,10 @@ SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
         lastIndex =
                 static_cast<int>(subsetGlyphIDs[subsetGlyphIDsLength - 1]) + 1;
     }
-    curRange = appendRange(&result, firstIndex);
+    WidthRange curRange(firstIndex);
 
     for (int gId = firstIndex; gId <= lastIndex; gId++) {
-        Data advance = kInvalidAdvance;
+        int16_t advance = kInvalidAdvance;
         if (gId < lastIndex) {
             // Get glyph id only when subset is nullptr, or the id is in subset.
             SkASSERT(!subsetGlyphIDs || (subsetIndex < subsetGlyphIDsLength &&
@@ -199,16 +147,16 @@ SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
         } else if (advance == kDontCareAdvance) {
             wildCardsInRun++;
             trailingWildCards++;
-        } else if (curRange->fAdvance.count() ==
+        } else if (curRange.fAdvance.count() ==
                    repeatedAdvances + 1 + wildCardsInRun) {  // All in run.
             if (lastAdvance == 0) {
-                resetRange(curRange, gId);
+                curRange.fStartId = gId;  // reset
+                curRange.fAdvance.setCount(0);
                 trailingWildCards = 0;
             } else if (repeatedAdvances + 1 >= 2 || trailingWildCards >= 4) {
-                finishRange(curRange, gId - 1,
-                            SkAdvancedTypefaceMetrics::WidthRange::kRun);
-                prevRange = curRange;
-                curRange = appendRange(&curRange->fNext, gId);
+                FinishRange(&curRange, gId - 1, WidthRange::kRun);
+                prevRange = fGlyphWidths.emplace_back(std::move(curRange));
+                curRange = WidthRange(gId);
                 trailingWildCards = 0;
             }
             repeatedAdvances = 0;
@@ -217,61 +165,57 @@ SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
         } else {
             if (lastAdvance == 0 &&
                     repeatedAdvances + 1 + wildCardsInRun >= 4) {
-                finishRange(curRange,
+                FinishRange(&curRange,
                             gId - repeatedAdvances - wildCardsInRun - 2,
-                            SkAdvancedTypefaceMetrics::WidthRange::kRange);
-                prevRange = curRange;
-                curRange = appendRange(&curRange->fNext, gId);
+                            WidthRange::kRange);
+                prevRange = fGlyphWidths.emplace_back(std::move(curRange));
+                curRange = WidthRange(gId);
                 trailingWildCards = 0;
             } else if (trailingWildCards >= 4 && repeatedAdvances + 1 < 2) {
-                finishRange(curRange,
-                            gId - trailingWildCards - 1,
-                            SkAdvancedTypefaceMetrics::WidthRange::kRange);
-                prevRange = curRange;
-                curRange = appendRange(&curRange->fNext, gId);
+                FinishRange(&curRange, gId - trailingWildCards - 1,
+                            WidthRange::kRange);
+                prevRange = fGlyphWidths.emplace_back(std::move(curRange));
+                curRange = WidthRange(gId);
                 trailingWildCards = 0;
             } else if (lastAdvance != 0 &&
                        (repeatedAdvances + 1 >= 3 ||
                         (repeatedAdvances + 1 >= 2 && wildCardsInRun >= 3))) {
-                finishRange(curRange,
+                FinishRange(&curRange,
                             gId - repeatedAdvances - wildCardsInRun - 2,
-                            SkAdvancedTypefaceMetrics::WidthRange::kRange);
+                            WidthRange::kRange);
+                (void)fGlyphWidths.emplace_back(std::move(curRange));
                 curRange =
-                    appendRange(&curRange->fNext,
-                                gId - repeatedAdvances - wildCardsInRun - 1);
-                curRange->fAdvance.append(1, &lastAdvance);
-                finishRange(curRange, gId - 1,
-                            SkAdvancedTypefaceMetrics::WidthRange::kRun);
-                prevRange = curRange;
-                curRange = appendRange(&curRange->fNext, gId);
+                        WidthRange(gId - repeatedAdvances - wildCardsInRun - 1);
+                curRange.fAdvance.append(1, &lastAdvance);
+                FinishRange(&curRange, gId - 1, WidthRange::kRun);
+                prevRange = fGlyphWidths.emplace_back(std::move(curRange));
+                curRange = WidthRange(gId);
                 trailingWildCards = 0;
             }
             repeatedAdvances = 0;
             wildCardsInRun = trailingWildCards;
             trailingWildCards = 0;
         }
-        curRange->fAdvance.append(1, &advance);
+        curRange.fAdvance.append(1, &advance);
         if (advance != kDontCareAdvance) {
             lastAdvance = advance;
         }
     }
-    if (curRange->fStartId == lastIndex) {
+    if (curRange.fStartId == lastIndex) {
         SkASSERT(prevRange);
         if (!prevRange) {
-            return nullptr;  // https://crbug.com/567031
+            fGlyphWidths.reset();
+            return;  // https://crbug.com/567031
         }
-        SkASSERT(prevRange->fNext->fStartId == lastIndex);
-        prevRange->fNext.reset();
     } else {
-        finishRange(curRange, lastIndex - 1,
-                    SkAdvancedTypefaceMetrics::WidthRange::kRange);
+        FinishRange(&curRange, lastIndex - 1, WidthRange::kRange);
+        fGlyphWidths.emplace_back(std::move(curRange));
     }
-    return result.release();
 }
 
 // Make AdvanceMetric template functions available for linking with typename
 // WidthRange and VerticalAdvanceRange.
-template SkAdvancedTypefaceMetrics::WidthRange* getAdvanceData(
+template void SkAdvancedTypefaceMetrics::setGlyphWidths(
         FT_Face face,
         int num_glyphs,
         const uint32_t* subsetGlyphIDs,
@@ -279,55 +223,30 @@ template SkAdvancedTypefaceMetrics::WidthRange* getAdvanceData(
         bool (*getAdvance)(FT_Face face, int gId, int16_t* data));
 
 #if defined(SK_BUILD_FOR_WIN)
-template SkAdvancedTypefaceMetrics::WidthRange* getAdvanceData(
+template void SkAdvancedTypefaceMetrics::setGlyphWidths(
         HDC hdc,
         int num_glyphs,
         const uint32_t* subsetGlyphIDs,
         uint32_t subsetGlyphIDsLength,
         bool (*getAdvance)(HDC hdc, int gId, int16_t* data));
-template SkAdvancedTypefaceMetrics::WidthRange* getAdvanceData(
+template void SkAdvancedTypefaceMetrics::setGlyphWidths(
         IDWriteFontFace* fontFace,
         int num_glyphs,
         const uint32_t* subsetGlyphIDs,
         uint32_t subsetGlyphIDsLength,
         bool (*getAdvance)(IDWriteFontFace* fontFace, int gId, int16_t* data));
 #elif defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)
-template SkAdvancedTypefaceMetrics::WidthRange* getAdvanceData(
+template void SkAdvancedTypefaceMetrics::setGlyphWidths(
         CTFontRef ctFont,
         int num_glyphs,
         const uint32_t* subsetGlyphIDs,
         uint32_t subsetGlyphIDsLength,
         bool (*getAdvance)(CTFontRef ctFont, int gId, int16_t* data));
 #endif
-template void resetRange(
-        SkAdvancedTypefaceMetrics::WidthRange* range,
-        int startId);
-template SkAdvancedTypefaceMetrics::WidthRange* appendRange(
-        SkAutoTDelete<SkAdvancedTypefaceMetrics::WidthRange >* nextSlot,
-        int startId);
-template void finishRange<int16_t>(
-        SkAdvancedTypefaceMetrics::WidthRange* range,
-        int endId,
-        SkAdvancedTypefaceMetrics::WidthRange::MetricType type);
-
-template void resetRange(
-        SkAdvancedTypefaceMetrics::VerticalAdvanceRange* range,
-        int startId);
-template SkAdvancedTypefaceMetrics::VerticalAdvanceRange* appendRange(
-        SkAutoTDelete<SkAdvancedTypefaceMetrics::VerticalAdvanceRange >*
-            nextSlot,
-        int startId);
-template void finishRange<SkAdvancedTypefaceMetrics::VerticalMetric>(
-        SkAdvancedTypefaceMetrics::VerticalAdvanceRange* range,
-        int endId,
-        SkAdvancedTypefaceMetrics::VerticalAdvanceRange::MetricType type);
-
 // additional declaration needed for testing with a face of an unknown type
-template SkAdvancedTypefaceMetrics::WidthRange* getAdvanceData(
+template void SkAdvancedTypefaceMetrics::setGlyphWidths(
         void* fontData,
         int num_glyphs,
         const uint32_t* subsetGlyphIDs,
         uint32_t subsetGlyphIDsLength,
         bool (*getAdvance)(void* fontData, int gId, int16_t* data));
-
-} // namespace skia_advanced_typeface_metrics_utils
diff --git a/src/core/SkAdvancedTypefaceMetrics.h b/src/core/SkAdvancedTypefaceMetrics.h
index eae7318215..5e7e59331f 100644
--- a/src/core/SkAdvancedTypefaceMetrics.h
+++ b/src/core/SkAdvancedTypefaceMetrics.h
@@ -14,34 +14,7 @@
 #include "SkString.h"
 #include "SkTDArray.h"
 #include "SkTemplates.h"
-
-// Whatever std::unique_ptr Clank's using doesn't seem to work with AdvanceMetric's
-// style of forward-declaration.  Probably just a bug in an old libc++ / libstdc++.
-// For now, hack around it with our own smart pointer.  It'd be nice to clean up.
-template <typename T>
-class SkHackyAutoTDelete : SkNoncopyable {
-public:
-    explicit SkHackyAutoTDelete(T* ptr = nullptr) : fPtr(ptr) {}
-    ~SkHackyAutoTDelete() { delete fPtr; }
-
-    T*        get() const { return fPtr; }
-    T* operator->() const { return fPtr; }
-
-    void reset(T* ptr = nullptr) {
-        if (ptr != fPtr) {
-            delete fPtr;
-            fPtr = ptr;
-        }
-    }
-    T* release() {
-        T* ptr = fPtr;
-        fPtr = nullptr;
-        return ptr;
-    }
-
-private:
-    T* fPtr;
-};
+#include "SkSinglyLinkedList.h"
 
 /** \class SkAdvancedTypefaceMetrics
 
@@ -68,6 +41,29 @@ public:
 
     ~SkAdvancedTypefaceMetrics();
 
+    /** Retrieve advance data for glyphs. Used by the PDF backend. It
+        calls underlying platform dependent API getAdvance to acquire
+        the data.
+        @param num_glyphs    Total number of glyphs in the given font.
+        @param glyphIDs      For per-glyph info, specify subset of the
+                             font by giving glyph ids.  Each integer
+                             represents a glyph id.  Passing nullptr
+                             means all glyphs in the font.
+        @param glyphIDsCount Number of elements in subsetGlyphIds.
+                             Ignored if glyphIDs is nullptr.
+        @param  getAdvance   A function that takes a glyph id and
+                             passes back advance data from the
+                             typeface.  Returns false on failure.
+    */
+    template <typename FontHandle>
+    void setGlyphWidths(FontHandle fontHandle,
+                        int num_glyphs,
+                        const uint32_t* subsetGlyphIDs,
+                        uint32_t subsetGlyphIDsLength,
+                        bool (*getAdvance)(FontHandle fontHandle,
+                                           int gId,
+                                           int16_t* data));
+
     SkString fFontName;
 
     enum FontType {
@@ -126,7 +122,22 @@ public:
         uint16_t fStartId;
         uint16_t fEndId;
         SkTDArray<Data> fAdvance;
-        SkHackyAutoTDelete<AdvanceMetric<Data> > fNext;
+        AdvanceMetric(uint16_t startId) : fStartId(startId) {}
+        AdvanceMetric(AdvanceMetric&& other)
+            : fType(other.fType)
+            , fStartId(other.fStartId)
+            , fEndId(other.fEndId) {
+            fAdvance.swap(other.fAdvance);
+        }
+        AdvanceMetric& operator=(AdvanceMetric&& other) {
+            fType = other.fType;
+            fStartId = other.fStartId;
+            fEndId = other.fEndId;
+            fAdvance.swap(other.fAdvance);
+            return *this;
+        }
+        AdvanceMetric(const AdvanceMetric&) = delete;
+        AdvanceMetric& operator=(const AdvanceMetric&) = delete;
     };
 
     struct VerticalMetric {
@@ -138,9 +149,9 @@ public:
     typedef AdvanceMetric<VerticalMetric> VerticalAdvanceRange;
 
     // This is indexed by glyph id.
-    SkAutoTDelete<WidthRange> fGlyphWidths;
+    SkSinglyLinkedList<WidthRange> fGlyphWidths;
     // Only used for Vertical CID fonts.
-    SkAutoTDelete<VerticalAdvanceRange> fVerticalMetrics;
+    SkSinglyLinkedList<VerticalAdvanceRange> fVerticalMetrics;
 
     // The names of each glyph, only populated for postscript fonts.
     SkAutoTDelete<SkAutoTArray<SkString> > fGlyphNames;
@@ -149,45 +160,13 @@ public:
     // kToUnicode_PerGlyphInfo is passed to GetAdvancedTypefaceMetrics.
     SkTDArray<SkUnichar> fGlyphToUnicode;
 
+    static void FinishRange(WidthRange* range,
+                            int endId,
+                            WidthRange::MetricType type);
+
 private:
     typedef SkRefCnt INHERITED;
 };
 
-namespace skia_advanced_typeface_metrics_utils {
-
-template <typename Data>
-void resetRange(SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
-                       int startId);
-
-template <typename Data, template<typename> class AutoTDelete>
-SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* appendRange(
-        AutoTDelete<SkAdvancedTypefaceMetrics::AdvanceMetric<Data> >* nextSlot,
-        int startId);
-
-template <typename Data>
-void finishRange(
-        SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
-        int endId,
-        typename SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::MetricType
-                type);
-
-/** Retrieve advance data for glyphs. Used by the PDF backend. It calls
-    underlying platform dependent API getAdvance to acquire the data.
-    @param num_glyphs    Total number of glyphs in the given font.
-    @param glyphIDs      For per-glyph info, specify subset of the font by
-                         giving glyph ids.  Each integer represents a glyph
-                         id.  Passing nullptr means all glyphs in the font.
-    @param glyphIDsCount Number of elements in subsetGlyphIds. Ignored if
-                         glyphIDs is nullptr.
-*/
-template <typename Data, typename FontHandle>
-SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
-        FontHandle fontHandle,
-        int num_glyphs,
-        const uint32_t* glyphIDs,
-        uint32_t glyphIDsCount,
-        bool (*getAdvance)(FontHandle fontHandle, int gId, Data* data));
-
-} // namespace skia_advanced_typeface_metrics_utils
 
 #endif
diff --git a/src/pdf/SkSinglyLinkedList.h b/src/core/SkSinglyLinkedList.h
index c7101141d6..b011204613 100644
--- a/src/pdf/SkSinglyLinkedList.h
+++ b/src/core/SkSinglyLinkedList.h
@@ -31,6 +31,7 @@ public:
     }
     T* back() { return fTail ? &fTail->fData : nullptr; }
     T* front() { return fHead ? &fHead->fData : nullptr; }
+    bool empty() const { return fHead == nullptr; }
     #ifdef SK_DEBUG
     int count() {  // O(n), debug only.
         int count = 0;
diff --git a/src/pdf/SkPDFFont.cpp b/src/pdf/SkPDFFont.cpp
index 8718596b8e..7a66bcd1e9 100644
--- a/src/pdf/SkPDFFont.cpp
+++ b/src/pdf/SkPDFFont.cpp
@@ -322,33 +322,36 @@ static void appendVerticalAdvance(
 
 template <typename Data>
 SkPDFArray* composeAdvanceData(
-        SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* advanceInfo,
+        const SkSinglyLinkedList<
+                SkAdvancedTypefaceMetrics::AdvanceMetric<Data>>& advanceInfo,
         uint16_t emSize,
-        void (*appendAdvance)(const Data& advance, uint16_t emSize,
+        void (*appendAdvance)(const Data& advance,
+                              uint16_t emSize,
                               SkPDFArray* array),
         Data* defaultAdvance) {
     SkPDFArray* result = new SkPDFArray();
-    for (; advanceInfo != nullptr; advanceInfo = advanceInfo->fNext.get()) {
-        switch (advanceInfo->fType) {
-            case SkAdvancedTypefaceMetrics::WidthRange::kDefault: {
-                SkASSERT(advanceInfo->fAdvance.count() == 1);
-                *defaultAdvance = advanceInfo->fAdvance[0];
+    for (const SkAdvancedTypefaceMetrics::AdvanceMetric<Data>& range :
+         advanceInfo) {
+        switch (range.fType) {
+            case SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::kDefault: {
+                SkASSERT(range.fAdvance.count() == 1);
+                *defaultAdvance = range.fAdvance[0];
                 break;
             }
-            case SkAdvancedTypefaceMetrics::WidthRange::kRange: {
+            case SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::kRange: {
                 auto advanceArray = sk_make_sp<SkPDFArray>();
-                for (int j = 0; j < advanceInfo->fAdvance.count(); j++)
-                    appendAdvance(advanceInfo->fAdvance[j], emSize,
+                for (int j = 0; j < range.fAdvance.count(); j++)
+                    appendAdvance(range.fAdvance[j], emSize,
                                   advanceArray.get());
-                result->appendInt(advanceInfo->fStartId);
+                result->appendInt(range.fStartId);
                 result->appendObject(std::move(advanceArray));
                 break;
             }
-            case SkAdvancedTypefaceMetrics::WidthRange::kRun: {
-                SkASSERT(advanceInfo->fAdvance.count() == 1);
-                result->appendInt(advanceInfo->fStartId);
-                result->appendInt(advanceInfo->fEndId);
-                appendAdvance(advanceInfo->fAdvance[0], emSize, result);
+            case SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::kRun: {
+                SkASSERT(range.fAdvance.count() == 1);
+                result->appendInt(range.fStartId);
+                result->appendInt(range.fEndId);
+                appendAdvance(range.fAdvance[0], emSize, result);
                 break;
             }
         }
@@ -1146,12 +1149,11 @@ bool SkPDFCIDFont::populate(const SkPDFGlyphSet* subset) {
     sysInfo->insertInt("Supplement", 0);
     this->insertObject("CIDSystemInfo", std::move(sysInfo));
 
-    if (fontInfo()->fGlyphWidths.get()) {
+    if (!fontInfo()->fGlyphWidths.empty()) {
         int16_t defaultWidth = 0;
-        sk_sp<SkPDFArray> widths(
-            composeAdvanceData(fontInfo()->fGlyphWidths.get(),
-                               fontInfo()->fEmSize, &appendWidth,
-                               &defaultWidth));
+        sk_sp<SkPDFArray> widths(composeAdvanceData(
+                fontInfo()->fGlyphWidths, fontInfo()->fEmSize, &appendWidth,
+                &defaultWidth));
         if (widths->size())
             this->insertObject("W", std::move(widths));
         if (defaultWidth != 0) {
@@ -1160,15 +1162,14 @@ bool SkPDFCIDFont::populate(const SkPDFGlyphSet* subset) {
                     scaleFromFontUnits(defaultWidth, fontInfo()->fEmSize));
         }
     }
-    if (fontInfo()->fVerticalMetrics.get()) {
+    if (!fontInfo()->fVerticalMetrics.empty()) {
         struct SkAdvancedTypefaceMetrics::VerticalMetric defaultAdvance;
         defaultAdvance.fVerticalAdvance = 0;
         defaultAdvance.fOriginXDisp = 0;
         defaultAdvance.fOriginYDisp = 0;
-        sk_sp<SkPDFArray> advances(
-            composeAdvanceData(fontInfo()->fVerticalMetrics.get(),
-                               fontInfo()->fEmSize, &appendVerticalAdvance,
-                               &defaultAdvance));
+        sk_sp<SkPDFArray> advances(composeAdvanceData(
+                fontInfo()->fVerticalMetrics, fontInfo()->fEmSize,
+                &appendVerticalAdvance, &defaultAdvance));
         if (advances->size())
             this->insertObject("W2", std::move(advances));
         if (defaultAdvance.fVerticalAdvance ||
@@ -1237,27 +1238,24 @@ bool SkPDFType1Font::addFontDescriptor(int16_t defaultWidth) {
 }
 
 bool SkPDFType1Font::populate(int16_t glyphID) {
-    SkASSERT(!fontInfo()->fVerticalMetrics.get());
-    SkASSERT(fontInfo()->fGlyphWidths.get());
+    SkASSERT(fontInfo()->fVerticalMetrics.empty());
+    SkASSERT(!fontInfo()->fGlyphWidths.empty());
 
     adjustGlyphRangeForSingleByteEncoding(glyphID);
 
     int16_t defaultWidth = 0;
     const SkAdvancedTypefaceMetrics::WidthRange* widthRangeEntry = nullptr;
-    const SkAdvancedTypefaceMetrics::WidthRange* widthEntry;
-    for (widthEntry = fontInfo()->fGlyphWidths.get();
-            widthEntry != nullptr;
-            widthEntry = widthEntry->fNext.get()) {
-        switch (widthEntry->fType) {
+    for (const auto& widthEntry : fontInfo()->fGlyphWidths) {
+        switch (widthEntry.fType) {
             case SkAdvancedTypefaceMetrics::WidthRange::kDefault:
-                defaultWidth = widthEntry->fAdvance[0];
+                defaultWidth = widthEntry.fAdvance[0];
                 break;
             case SkAdvancedTypefaceMetrics::WidthRange::kRun:
                 SkASSERT(false);
                 break;
             case SkAdvancedTypefaceMetrics::WidthRange::kRange:
                 SkASSERT(widthRangeEntry == nullptr);
-                widthRangeEntry = widthEntry;
+                widthRangeEntry = &widthEntry;
                 break;
         }
     }
diff --git a/src/ports/SkFontHost_FreeType.cpp b/src/ports/SkFontHost_FreeType.cpp
index b53364eacb..30e5fb340f 100644
--- a/src/ports/SkFontHost_FreeType.cpp
+++ b/src/ports/SkFontHost_FreeType.cpp
@@ -58,8 +58,6 @@
 //#define SK_FONTHOST_FREETYPE_RUNTIME_VERSION
 //#define SK_GAMMA_APPLY_TO_A8
 
-using namespace skia_advanced_typeface_metrics_utils;
-
 static bool isLCD(const SkScalerContext::Rec& rec) {
     return SkMask::kLCD16_Format == rec.fMaskFormat;
 }
@@ -591,13 +589,14 @@ SkAdvancedTypefaceMetrics* SkTypeface_FreeType::onGetAdvancedTypefaceMetrics(
 
     if (perGlyphInfo & kHAdvance_PerGlyphInfo) {
         if (FT_IS_FIXED_WIDTH(face)) {
-            appendRange(&info->fGlyphWidths, 0);
+            SkAdvancedTypefaceMetrics::WidthRange range(0);
             int16_t advance = face->max_advance_width;
-            info->fGlyphWidths->fAdvance.append(1, &advance);
-            finishRange(info->fGlyphWidths.get(), 0,
-                        SkAdvancedTypefaceMetrics::WidthRange::kDefault);
+            range.fAdvance.append(1, &advance);
+            SkAdvancedTypefaceMetrics::FinishRange(
+                    &range, 0, SkAdvancedTypefaceMetrics::WidthRange::kDefault);
+            info->fGlyphWidths.emplace_back(std::move(range));
         } else if (!cid) {
-            appendRange(&info->fGlyphWidths, 0);
+            SkAdvancedTypefaceMetrics::WidthRange range(0);
             // So as to not blow out the stack, get advances in batches.
             for (int gID = 0; gID < face->num_glyphs; gID += 128) {
                 FT_Fixed advances[128];
@@ -608,18 +607,16 @@ SkAdvancedTypefaceMetrics* SkTypeface_FreeType::onGetAdvancedTypefaceMetrics(
                 FT_Get_Advances(face, gID, advanceCount, FT_LOAD_NO_SCALE, advances);
                 for (int i = 0; i < advanceCount; i++) {
                     int16_t advance = advances[i];
-                    info->fGlyphWidths->fAdvance.append(1, &advance);
+                    range.fAdvance.append(1, &advance);
                 }
             }
-            finishRange(info->fGlyphWidths.get(), face->num_glyphs - 1,
-                        SkAdvancedTypefaceMetrics::WidthRange::kRange);
+            SkAdvancedTypefaceMetrics::FinishRange(
+                    &range, face->num_glyphs - 1,
+                    SkAdvancedTypefaceMetrics::WidthRange::kRange);
+            info->fGlyphWidths.emplace_back(std::move(range));
         } else {
-            info->fGlyphWidths.reset(
-                getAdvanceData(face,
-                               face->num_glyphs,
-                               glyphIDs,
-                               glyphIDsCount,
-                               &getWidthAdvance));
+            info->setGlyphWidths(face, face->num_glyphs, glyphIDs,
+                                 glyphIDsCount, &getWidthAdvance);
         }
     }
 
diff --git a/src/ports/SkFontHost_mac.cpp b/src/ports/SkFontHost_mac.cpp
index 8593b39611..dc13331735 100644
--- a/src/ports/SkFontHost_mac.cpp
+++ b/src/ports/SkFontHost_mac.cpp
@@ -1619,17 +1619,14 @@ SkAdvancedTypefaceMetrics* SkTypeface_Mac::onGetAdvancedTypefaceMetrics(
 
     if (perGlyphInfo & kHAdvance_PerGlyphInfo) {
         if (info->fStyle & SkAdvancedTypefaceMetrics::kFixedPitch_Style) {
-            skia_advanced_typeface_metrics_utils::appendRange(&info->fGlyphWidths, 0);
-            info->fGlyphWidths->fAdvance.append(1, &min_width);
-            skia_advanced_typeface_metrics_utils::finishRange(info->fGlyphWidths.get(), 0,
-                        SkAdvancedTypefaceMetrics::WidthRange::kDefault);
+            SkAdvancedTypefaceMetrics::WidthRange range(0);
+            range.fAdvance.append(1, &min_width);
+            SkAdvancedTypefaceMetrics::FinishRange(
+                    &range, 0, SkAdvancedTypefaceMetrics::WidthRange::kDefault);
+            info->fGlyphWidths.emplace_back(std::move(range));
         } else {
-            info->fGlyphWidths.reset(
-                skia_advanced_typeface_metrics_utils::getAdvanceData(ctFont.get(),
-                               SkToInt(glyphCount),
-                               glyphIDs,
-                               glyphIDsCount,
-                               &getWidthAdvance));
+            info->setGlyphWidths(ctFont.get(), SkToInt(glyphCount), glyphIDs,
+                                 glyphIDsCount, &getWidthAdvance);
         }
     }
     return info;
diff --git a/src/ports/SkFontHost_win.cpp b/src/ports/SkFontHost_win.cpp
index db90915aca..7c0a639b4b 100644
--- a/src/ports/SkFontHost_win.cpp
+++ b/src/ports/SkFontHost_win.cpp
@@ -86,8 +86,6 @@ static bool needToRenderWithSkia(const SkScalerContext::Rec& rec) {
     return rec.getHinting() == SkPaint::kNo_Hinting || rec.getHinting() == SkPaint::kSlight_Hinting;
 }
 
-using namespace skia_advanced_typeface_metrics_utils;
-
 static void tchar_to_skstring(const TCHAR t[], SkString* s) {
 #ifdef UNICODE
     size_t sSize = WideCharToMultiByte(CP_UTF8, 0, t, -1, nullptr, 0, nullptr, nullptr);
@@ -1835,17 +1833,14 @@ SkAdvancedTypefaceMetrics* LogFontTypeface::onGetAdvancedTypefaceMetrics(
 
     if (perGlyphInfo & kHAdvance_PerGlyphInfo) {
         if (info->fStyle & SkAdvancedTypefaceMetrics::kFixedPitch_Style) {
-            appendRange(&info->fGlyphWidths, 0);
-            info->fGlyphWidths->fAdvance.append(1, &min_width);
-            finishRange(info->fGlyphWidths.get(), 0,
-                        SkAdvancedTypefaceMetrics::WidthRange::kDefault);
+            SkAdvancedTypefaceMetrics::WidthRange range(0);
+            range.fAdvance.append(1, &min_width);
+            SkAdvancedTypefaceMetrics::FinishRange(
+                    &range, 0, SkAdvancedTypefaceMetrics::WidthRange::kDefault);
+            info->fGlyphWidths.emplace_back(std::move(range));
         } else {
-            info->fGlyphWidths.reset(
-                getAdvanceData(hdc,
-                               glyphCount,
-                               glyphIDs,
-                               glyphIDsCount,
-                               &getWidthAdvance));
+            info->setGlyphWidths(hdc, glyphCount, glyphIDs,
+                                 glyphIDsCount, &getWidthAdvance);
         }
     }
 
diff --git a/src/ports/SkTypeface_win_dw.cpp b/src/ports/SkTypeface_win_dw.cpp
index 18c63a5089..de599d67e5 100644
--- a/src/ports/SkTypeface_win_dw.cpp
+++ b/src/ports/SkTypeface_win_dw.cpp
@@ -284,8 +284,6 @@ void DWriteFontTypeface::onFilterRec(SkScalerContext::Rec* rec) const {
 ///////////////////////////////////////////////////////////////////////////////
 //PDF Support
 
-using namespace skia_advanced_typeface_metrics_utils;
-
 // Construct Glyph to Unicode table.
 // Unicode code points that require conjugate pairs in utf16 are not
 // supported.
@@ -444,19 +442,16 @@ SkAdvancedTypefaceMetrics* DWriteFontTypeface::onGetAdvancedTypefaceMetrics(
 
     if (perGlyphInfo & kHAdvance_PerGlyphInfo) {
         if (fixedWidth) {
-            appendRange(&info->fGlyphWidths, 0);
+            SkAdvancedTypefaceMetrics::WidthRange range(0);
             int16_t advance;
             getWidthAdvance(fDWriteFontFace.get(), 1, &advance);
-            info->fGlyphWidths->fAdvance.append(1, &advance);
-            finishRange(info->fGlyphWidths.get(), 0,
-                        SkAdvancedTypefaceMetrics::WidthRange::kDefault);
+            range.fAdvance.append(1, &advance);
+            SkAdvancedTypefaceMetrics::FinishRange(
+                    &range, 0, SkAdvancedTypefaceMetrics::WidthRange::kDefault);
+            info->fGlyphWidths.emplace_back(std::move(range));
         } else {
-            info->fGlyphWidths.reset(
-                getAdvanceData(fDWriteFontFace.get(),
-                               glyphCount,
-                               glyphIDs,
-                               glyphIDsCount,
-                               getWidthAdvance));
+            info->setGlyphWidths(fDWriteFontFace.get(), glyphCount, glyphIDs,
+                                 glyphIDsCount, getWidthAdvance);
         }
     }
 
diff --git a/tests/WArrayTest.cpp b/tests/WArrayTest.cpp
index 40128fa2b4..55f2a10b01 100644
--- a/tests/WArrayTest.cpp
+++ b/tests/WArrayTest.cpp
@@ -10,8 +10,6 @@
 // Include the implementation so we can make an appropriate template instance.
 #include "SkAdvancedTypefaceMetrics.h"
 
-using namespace skia_advanced_typeface_metrics_utils;
-
 // Negative values and zeros in a range plus trailing zeros.
 //                        0  1   2  3  4  5  6  7  8  9 10 11 12 13 14
 static const int16_t data1[] = {-1, 0, -3, 4, 5, 6, 7, 0, 0, 0, 8, 0, 0, 0, 0};
@@ -98,34 +96,35 @@ static const char* expected14 = "0[1] 5[2]";
 static const uint32_t subset14[] = {0, 5};
 static const char* expectedSubset14 = "0[1] 5[2]";
 
-static SkString stringify_advance_data(SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>* data) {
+static SkString stringify_advance_data(const SkSinglyLinkedList<
+        SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>>& list) {
     SkString result;
     bool leadingSpace = false;
-    while (data != nullptr) {
-      if (leadingSpace) {
-        result.append(" ");
-      } else {
-        leadingSpace = true;
-      }
-      switch(data->fType) {
-        case SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>::kRun:
-          result.appendf("%d %d %d", data->fStartId, data->fEndId, data->fAdvance[0]);
-          break;
-        case SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>::kRange:
-          result.appendf("%d[", data->fStartId);
-          for (int i = 0; i < data->fAdvance.count(); ++i) {
-            if (i > 0) {
-              result.append(" ");
-            }
-            result.appendf("%d", data->fAdvance[i]);
-          }
-          result.append("]");
-          break;
-        case SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>::kDefault:
-          result.appendf("<Default=%d>", data->fAdvance[0]);
-          break;
-      }
-      data = data->fNext.get();
+    for (const SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>& data : list) {
+        if (leadingSpace) {
+            result.append(" ");
+        } else {
+            leadingSpace = true;
+        }
+        switch (data.fType) {
+            case SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>::kRun:
+                result.appendf("%d %d %d", data.fStartId, data.fEndId,
+                               data.fAdvance[0]);
+                break;
+            case SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>::kRange:
+                result.appendf("%d[", data.fStartId);
+                for (int i = 0; i < data.fAdvance.count(); ++i) {
+                    if (i > 0) {
+                        result.append(" ");
+                    }
+                    result.appendf("%d", data.fAdvance[i]);
+                }
+                result.append("]");
+                break;
+            case SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>::kDefault:
+                result.appendf("<Default=%d>", data.fAdvance[0]);
+                break;
+        }
     }
     return result;
 }
@@ -161,10 +160,11 @@ class TestWData {
     }
 
     void runTest(skiatest::Reporter* reporter) {
-        SkAutoTDelete<SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t> > result;
-        result.reset(getAdvanceData((void*)this, fAdvancesLen, fSubset, fSubsetLen, getAdvance));
+        SkAdvancedTypefaceMetrics metrics;
+        metrics.setGlyphWidths((void*)this, fAdvancesLen, fSubset, fSubsetLen,
+                               getAdvance);
 
-        SkString stringResult = stringify_advance_data(result);
+        SkString stringResult = stringify_advance_data(metrics.fGlyphWidths);
         if (!stringResult.equals(fExpected)) {
             ERRORF(reporter, "Expected: %s\n  Result: %s\n", fExpected, stringResult.c_str());
         }