Pass arguments to SkRecords structs by const&.

This has the effect of using delay_copy() on every argument,
obviating the need for delay_copy() and, crucially, having
to remember to call delay_copy().

All these constructors are fully inlined, so we'll never pay
a penalty for passing small things by reference... the compiler
can see that and just pass by value.

BUG=skia:

Review URL: https://codereview.chromium.org/1215523004

2 files changed, 59 insertions, 77 deletions

diff --git a/src/core/SkRecorder.cpp b/src/core/SkRecorder.cpp
index c27405575c..6d7e5ee90b 100644
--- a/src/core/SkRecorder.cpp
+++ b/src/core/SkRecorder.cpp
@@ -69,27 +69,6 @@ void SkRecorder::forgetRecord() {
 // For methods which must call back into SkCanvas.
 #define INHERITED(method, ...) this->SkCanvas::method(__VA_ARGS__)
 
-// The structs we're creating all copy their constructor arguments.  Given the way the SkRecords
-// framework works, sometimes they happen to technically be copied twice, which is fine and elided
-// into a single copy unless the class has a non-trivial copy constructor.  For classes with
-// non-trivial copy constructors, we skip the first copy (and its destruction) by wrapping the value
-// with delay_copy(), forcing the argument to be passed by const&.
-//
-// This is used below for SkBitmap, SkPaint, SkPath, and SkRegion, which all have non-trivial copy
-// constructors and destructors.  You'll know you've got a good candidate T if you see ~T() show up
-// unexpectedly on a profile of record time.  Otherwise don't bother.
-template <typename T>
-class Reference {
-public:
-    Reference(const T& x) : fX(x) {}
-    operator const T&() const { return fX; }
-private:
-    const T& fX;
-};
-
-template <typename T>
-static Reference<T> delay_copy(const T& x) { return Reference<T>(x); }
-
 // Use copy() only for optional arguments, to be copied if present or skipped if not.
 // (For most types we just pass by value and let copy constructors do their thing.)
 template <typename T>
@@ -142,31 +121,31 @@ void SkRecorder::flushMiniRecorder() {
 }
 
 void SkRecorder::onDrawPaint(const SkPaint& paint) {
-    APPEND(DrawPaint, delay_copy(paint));
+    APPEND(DrawPaint, paint);
 }
 
 void SkRecorder::onDrawPoints(PointMode mode,
                               size_t count,
                               const SkPoint pts[],
                               const SkPaint& paint) {
-    APPEND(DrawPoints, delay_copy(paint), mode, SkToUInt(count), this->copy(pts, count));
+    APPEND(DrawPoints, paint, mode, SkToUInt(count), this->copy(pts, count));
 }
 
 void SkRecorder::onDrawRect(const SkRect& rect, const SkPaint& paint) {
     TRY_MINIRECORDER(drawRect, rect, paint);
-    APPEND(DrawRect, delay_copy(paint), rect);
+    APPEND(DrawRect, paint, rect);
 }
 
 void SkRecorder::onDrawOval(const SkRect& oval, const SkPaint& paint) {
-    APPEND(DrawOval, delay_copy(paint), oval);
+    APPEND(DrawOval, paint, oval);
 }
 
 void SkRecorder::onDrawRRect(const SkRRect& rrect, const SkPaint& paint) {
-    APPEND(DrawRRect, delay_copy(paint), rrect);
+    APPEND(DrawRRect, paint, rrect);
 }
 
 void SkRecorder::onDrawDRRect(const SkRRect& outer, const SkRRect& inner, const SkPaint& paint) {
-    APPEND(DrawDRRect, delay_copy(paint), outer, inner);
+    APPEND(DrawDRRect, paint, outer, inner);
 }
 
 void SkRecorder::onDrawDrawable(SkDrawable* drawable) {
@@ -179,14 +158,14 @@ void SkRecorder::onDrawDrawable(SkDrawable* drawable) {
 
 void SkRecorder::onDrawPath(const SkPath& path, const SkPaint& paint) {
     TRY_MINIRECORDER(drawPath, path, paint);
-    APPEND(DrawPath, delay_copy(paint), delay_copy(path));
+    APPEND(DrawPath, paint, path);
 }
 
 void SkRecorder::onDrawBitmap(const SkBitmap& bitmap,
                               SkScalar left,
                               SkScalar top,
                               const SkPaint* paint) {
-    APPEND(DrawBitmap, this->copy(paint), delay_copy(bitmap), left, top);
+    APPEND(DrawBitmap, this->copy(paint), bitmap, left, top);
 }
 
 void SkRecorder::onDrawBitmapRect(const SkBitmap& bitmap,
@@ -196,19 +175,19 @@ void SkRecorder::onDrawBitmapRect(const SkBitmap& bitmap,
                                   DrawBitmapRectFlags flags) {
     if (kBleed_DrawBitmapRectFlag == flags) {
         APPEND(DrawBitmapRectToRectBleed,
-               this->copy(paint), delay_copy(bitmap), this->copy(src), dst);
+               this->copy(paint), bitmap, this->copy(src), dst);
         return;
     }
     SkASSERT(kNone_DrawBitmapRectFlag == flags);
     APPEND(DrawBitmapRectToRect,
-           this->copy(paint), delay_copy(bitmap), this->copy(src), dst);
+           this->copy(paint), bitmap, this->copy(src), dst);
 }
 
 void SkRecorder::onDrawBitmapNine(const SkBitmap& bitmap,
                                   const SkIRect& center,
                                   const SkRect& dst,
                                   const SkPaint* paint) {
-    APPEND(DrawBitmapNine, this->copy(paint), delay_copy(bitmap), center, dst);
+    APPEND(DrawBitmapNine, this->copy(paint), bitmap, center, dst);
 }
 
 void SkRecorder::onDrawImage(const SkImage* image, SkScalar left, SkScalar top,
@@ -228,20 +207,20 @@ void SkRecorder::onDrawImageNine(const SkImage* image, const SkIRect& center,
 }
 
 void SkRecorder::onDrawSprite(const SkBitmap& bitmap, int left, int top, const SkPaint* paint) {
-    APPEND(DrawSprite, this->copy(paint), delay_copy(bitmap), left, top);
+    APPEND(DrawSprite, this->copy(paint), bitmap, left, top);
 }
 
 void SkRecorder::onDrawText(const void* text, size_t byteLength,
                             SkScalar x, SkScalar y, const SkPaint& paint) {
     APPEND(DrawText,
-           delay_copy(paint), this->copy((const char*)text, byteLength), byteLength, x, y);
+           paint, this->copy((const char*)text, byteLength), byteLength, x, y);
 }
 
 void SkRecorder::onDrawPosText(const void* text, size_t byteLength,
                                const SkPoint pos[], const SkPaint& paint) {
     const unsigned points = paint.countText(text, byteLength);
     APPEND(DrawPosText,
-           delay_copy(paint),
+           paint,
            this->copy((const char*)text, byteLength),
            byteLength,
            this->copy(pos, points));
@@ -251,7 +230,7 @@ void SkRecorder::onDrawPosTextH(const void* text, size_t byteLength,
                                 const SkScalar xpos[], SkScalar constY, const SkPaint& paint) {
     const unsigned points = paint.countText(text, byteLength);
     APPEND(DrawPosTextH,
-           delay_copy(paint),
+           paint,
            this->copy((const char*)text, byteLength),
            SkToUInt(byteLength),
            constY,
@@ -261,17 +240,17 @@ void SkRecorder::onDrawPosTextH(const void* text, size_t byteLength,
 void SkRecorder::onDrawTextOnPath(const void* text, size_t byteLength, const SkPath& path,
                                   const SkMatrix* matrix, const SkPaint& paint) {
     APPEND(DrawTextOnPath,
-           delay_copy(paint),
+           paint,
            this->copy((const char*)text, byteLength),
            byteLength,
-           delay_copy(path),
+           path,
            matrix ? *matrix : SkMatrix::I());
 }
 
 void SkRecorder::onDrawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y,
                                 const SkPaint& paint) {
     TRY_MINIRECORDER(drawTextBlob, blob, x, y, paint);
-    APPEND(DrawTextBlob, delay_copy(paint), blob, x, y);
+    APPEND(DrawTextBlob, paint, blob, x, y);
 }
 
 void SkRecorder::onDrawPicture(const SkPicture* pic, const SkMatrix* matrix, const SkPaint* paint) {
@@ -284,7 +263,7 @@ void SkRecorder::onDrawVertices(VertexMode vmode,
                                 const SkPoint texs[], const SkColor colors[],
                                 SkXfermode* xmode,
                                 const uint16_t indices[], int indexCount, const SkPaint& paint) {
-    APPEND(DrawVertices, delay_copy(paint),
+    APPEND(DrawVertices, paint,
                          vmode,
                          vertexCount,
                          this->copy(vertices, vertexCount),
@@ -297,7 +276,7 @@ void SkRecorder::onDrawVertices(VertexMode vmode,
 
 void SkRecorder::onDrawPatch(const SkPoint cubics[12], const SkColor colors[4],
                              const SkPoint texCoords[4], SkXfermode* xmode, const SkPaint& paint) {
-    APPEND(DrawPatch, delay_copy(paint),
+    APPEND(DrawPatch, paint,
            cubics ? this->copy(cubics, SkPatchUtils::kNumCtrlPts) : NULL,
            colors ? this->copy(colors, SkPatchUtils::kNumCorners) : NULL,
            texCoords ? this->copy(texCoords, SkPatchUtils::kNumCorners) : NULL,
@@ -360,11 +339,11 @@ void SkRecorder::onClipRRect(const SkRRect& rrect, SkRegion::Op op, ClipEdgeStyl
 void SkRecorder::onClipPath(const SkPath& path, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
     INHERITED(onClipPath, path, op, edgeStyle);
     SkRecords::RegionOpAndAA opAA(op, kSoft_ClipEdgeStyle == edgeStyle);
-    APPEND(ClipPath, this->devBounds(), delay_copy(path), opAA);
+    APPEND(ClipPath, this->devBounds(), path, opAA);
 }
 
 void SkRecorder::onClipRegion(const SkRegion& deviceRgn, SkRegion::Op op) {
     INHERITED(onClipRegion, deviceRgn, op);
-    APPEND(ClipRegion, this->devBounds(), delay_copy(deviceRgn), op);
+    APPEND(ClipRegion, this->devBounds(), deviceRgn, op);
 }
 
diff --git a/src/core/SkRecords.h b/src/core/SkRecords.h
index 8e778bf7a2..4c9833cfc0 100644
--- a/src/core/SkRecords.h
+++ b/src/core/SkRecords.h
@@ -75,44 +75,43 @@ struct T {                              \
     static const Type kType = T##_Type; \
 };
 
-// We try to be flexible about the types the constructors take.  Instead of requring the exact type
-// A here, we take any type Z which implicitly casts to A.  This allows the delay_copy() trick to
-// work, allowing the caller to decide whether to pass by value or by const&.
+// Instead of requring the exact type A here, we take any type Z which implicitly casts to A.
+// This lets our wrappers like ImmutableBitmap work seamlessly.
 
 #define RECORD1(T, A, a)                \
 struct T {                              \
     static const Type kType = T##_Type; \
     T() {}                              \
     template <typename Z>               \
-    T(Z a) : a(a) {}                    \
+    T(const Z& a) : a(a) {}             \
     A a;                                \
 };
 
-#define RECORD2(T, A, a, B, b)          \
-struct T {                              \
-    static const Type kType = T##_Type; \
-    T() {}                              \
-    template <typename Z, typename Y>   \
-    T(Z a, Y b) : a(a), b(b) {}         \
-    A a; B b;                           \
+#define RECORD2(T, A, a, B, b)                \
+struct T {                                    \
+    static const Type kType = T##_Type;       \
+    T() {}                                    \
+    template <typename Z, typename Y>         \
+    T(const Z& a, const Y& b) : a(a), b(b) {} \
+    A a; B b;                                 \
 };
 
-#define RECORD3(T, A, a, B, b, C, c)              \
-struct T {                                        \
-    static const Type kType = T##_Type;           \
-    T() {}                                        \
-    template <typename Z, typename Y, typename X> \
-    T(Z a, Y b, X c) : a(a), b(b), c(c) {}        \
-    A a; B b; C c;                                \
+#define RECORD3(T, A, a, B, b, C, c)                            \
+struct T {                                                      \
+    static const Type kType = T##_Type;                         \
+    T() {}                                                      \
+    template <typename Z, typename Y, typename X>               \
+    T(const Z& a, const Y& b, const X& c) : a(a), b(b), c(c) {} \
+    A a; B b; C c;                                              \
 };
 
-#define RECORD4(T, A, a, B, b, C, c, D, d)                    \
-struct T {                                                    \
-    static const Type kType = T##_Type;                       \
-    T() {}                                                    \
-    template <typename Z, typename Y, typename X, typename W> \
-    T(Z a, Y b, X c, W d) : a(a), b(b), c(c), d(d) {}         \
-    A a; B b; C c; D d;                                       \
+#define RECORD4(T, A, a, B, b, C, c, D, d)                                        \
+struct T {                                                                        \
+    static const Type kType = T##_Type;                                           \
+    T() {}                                                                        \
+    template <typename Z, typename Y, typename X, typename W>                     \
+    T(const Z& a, const Y& b, const X& c, const W& d) : a(a), b(b), c(c), d(d) {} \
+    A a; B b; C c; D d;                                                           \
 };
 
 #define RECORD5(T, A, a, B, b, C, c, D, d, E, e)                          \
@@ -120,19 +119,23 @@ struct T {                                                                \
     static const Type kType = T##_Type;                                   \
     T() {}                                                                \
     template <typename Z, typename Y, typename X, typename W, typename V> \
-    T(Z a, Y b, X c, W d, V e) : a(a), b(b), c(c), d(d), e(e) {}          \
+    T(const Z& a, const Y& b, const X& c, const W& d, const V& e)         \
+        : a(a), b(b), c(c), d(d), e(e) {}                                 \
     A a; B b; C c; D d; E e;                                              \
 };
 
-#define RECORD8(T, A, a, B, b, C, c, D, d, E, e, F, f, G, g, H, h)        \
-struct T {                                                                \
-    static const Type kType = T##_Type;                                   \
-    T() {}                                                                \
-    template <typename Z, typename Y, typename X, typename W, typename V, typename U, typename S, typename R> \
-    T(Z a, Y b, X c, W d, V e, U f, S g, R h) : a(a), b(b), c(c), d(d), e(e), f(f), g(g), h(h) {} \
-    A a; B b; C c; D d; E e; F f; G g; H h;                               \
+#define RECORD8(T, A, a, B, b, C, c, D, d, E, e, F, f, G, g, H, h) \
+struct T {                                                         \
+    static const Type kType = T##_Type;                            \
+    T() {}                                                         \
+    template <typename Z, typename Y, typename X, typename W,      \
+              typename V, typename U, typename S, typename R>      \
+    T(const Z& a, const Y& b, const X& c, const W& d,              \
+      const V& e, const U& f, const S& g, const R& h)              \
+        : a(a), b(b), c(c), d(d), e(e), f(f), g(g), h(h) {}        \
+    A a; B b; C c; D d; E e; F f; G g; H h;                        \
 };
-    
+
 #define ACT_AS_PTR(ptr)                 \
     operator T*() const { return ptr; } \
     T* operator->() const { return ptr; }