Dont try to draw glyphs with unexpected mask formats

BUG=510931

Review URL: https://codereview.chromium.org/1269743003

5 files changed, 32 insertions, 10 deletions

diff --git a/src/gpu/GrAtlasTextContext.cpp b/src/gpu/GrAtlasTextContext.cpp
index f3d6eafb2e..f5867ba9cb 100644
--- a/src/gpu/GrAtlasTextContext.cpp
+++ b/src/gpu/GrAtlasTextContext.cpp
@@ -1681,7 +1681,8 @@ public:
                                  glyph->fMaskFormat == this->maskFormat());
 
                         if (!fFontCache->hasGlyph(glyph) &&
-                            !strike->addGlyphToAtlas(batchTarget, glyph, scaler, skGlyph)) {
+                            !strike->addGlyphToAtlas(batchTarget, glyph, scaler, skGlyph,
+                                                     maskFormat)) {
                             this->flush(batchTarget, &flushInfo);
                             batchTarget->initDraw(gp, pipeline);
                             brokenRun = glyphIdx > 0;
@@ -1689,7 +1690,8 @@ public:
                             SkDEBUGCODE(bool success =) strike->addGlyphToAtlas(batchTarget,
                                                                                 glyph,
                                                                                 scaler,
-                                                                                skGlyph);
+                                                                                skGlyph,
+                                                                                maskFormat);
                             SkASSERT(success);
                         }
                         fFontCache->addGlyphToBulkAndSetUseToken(&info.fBulkUseToken, glyph,
diff --git a/src/gpu/GrBatchFontCache.cpp b/src/gpu/GrBatchFontCache.cpp
index ecaa91e74d..dc5b43a547 100644
--- a/src/gpu/GrBatchFontCache.cpp
+++ b/src/gpu/GrBatchFontCache.cpp
@@ -196,7 +196,8 @@ void GrBatchTextStrike::removeID(GrBatchAtlas::AtlasID id) {
 }
 
 bool GrBatchTextStrike::addGlyphToAtlas(GrBatchTarget* batchTarget, GrGlyph* glyph,
-                                        GrFontScaler* scaler, const SkGlyph& skGlyph) {
+                                        GrFontScaler* scaler, const SkGlyph& skGlyph,
+                                        GrMaskFormat expectedMaskFormat) {
     SkASSERT(glyph);
     SkASSERT(scaler);
     SkASSERT(fCache.find(glyph->fPackedID));
@@ -204,7 +205,7 @@ bool GrBatchTextStrike::addGlyphToAtlas(GrBatchTarget* batchTarget, GrGlyph* gly
 
     SkAutoUnref ar(SkSafeRef(scaler));
 
-    int bytesPerPixel = GrMaskFormatBytesPerPixel(glyph->fMaskFormat);
+    int bytesPerPixel = GrMaskFormatBytesPerPixel(expectedMaskFormat);
 
     size_t size = glyph->fBounds.area() * bytesPerPixel;
     SkAutoSMalloc<1024> storage(size);
@@ -216,12 +217,13 @@ bool GrBatchTextStrike::addGlyphToAtlas(GrBatchTarget* batchTarget, GrGlyph* gly
         }
     } else {
         if (!scaler->getPackedGlyphImage(skGlyph, glyph->width(), glyph->height(),
-                                         glyph->width() * bytesPerPixel, storage.get())) {
+                                         glyph->width() * bytesPerPixel, expectedMaskFormat,
+                                         storage.get())) {
             return false;
         }
     }
 
-    bool success = fBatchFontCache->addToAtlas(this, &glyph->fID, batchTarget, glyph->fMaskFormat,
+    bool success = fBatchFontCache->addToAtlas(this, &glyph->fID, batchTarget, expectedMaskFormat,
                                                glyph->width(), glyph->height(),
                                                storage.get(), &glyph->fAtlasLocation);
     if (success) {
diff --git a/src/gpu/GrBatchFontCache.h b/src/gpu/GrBatchFontCache.h
index 33f313c912..447fc3f991 100644
--- a/src/gpu/GrBatchFontCache.h
+++ b/src/gpu/GrBatchFontCache.h
@@ -40,8 +40,13 @@ public:
         return glyph;
     }
 
-    // returns true if glyph successfully added to texture atlas, false otherwise
-    bool addGlyphToAtlas(GrBatchTarget*, GrGlyph*, GrFontScaler*, const SkGlyph&);
+    // returns true if glyph successfully added to texture atlas, false otherwise.  If the glyph's
+    // mask format has changed, then addGlyphToAtlas will draw a clear box.  This will almost never
+    // happen.
+    // TODO we can handle some of these cases if we really want to, but the long term solution is to
+    // get the actual glyph image itself when we get the glyph metrics.
+    bool addGlyphToAtlas(GrBatchTarget*, GrGlyph*, GrFontScaler*, const SkGlyph&,
+                         GrMaskFormat expectedMaskFormat);
 
     // testing
     int countGlyphs() const { return fCache.count(); }
diff --git a/src/gpu/GrFontScaler.cpp b/src/gpu/GrFontScaler.cpp
index 84fd58133c..a9d5abff4e 100644
--- a/src/gpu/GrFontScaler.cpp
+++ b/src/gpu/GrFontScaler.cpp
@@ -103,7 +103,7 @@ void expand_bits(INT_TYPE* dst,
 }
 
 bool GrFontScaler::getPackedGlyphImage(const SkGlyph& glyph, int width, int height, int dstRB,
-                                       void* dst) {
+                                       GrMaskFormat expectedMaskFormat, void* dst) {
     SkASSERT(glyph.fWidth == width);
     SkASSERT(glyph.fHeight == height);
     const void* src = fStrike->findImage(glyph);
@@ -111,6 +111,18 @@ bool GrFontScaler::getPackedGlyphImage(const SkGlyph& glyph, int width, int heig
         return false;
     }
 
+    // crbug:510931
+    // Retrieving the image from the cache can actually change the mask format.  This case is very
+    // uncommon so for now we just draw a clear box for these glyphs.
+    if (getPackedGlyphMaskFormat(glyph) != expectedMaskFormat) {
+        const int bpp = GrMaskFormatBytesPerPixel(expectedMaskFormat);
+        for (int y = 0; y < height; y++) {
+            sk_bzero(dst, width * bpp);
+            dst = (char*)dst + dstRB;
+        }
+        return true;
+    }
+
     int srcRB = glyph.rowBytes();
     // The windows font host sometimes has BW glyphs in a non-BW strike. So it is important here to
     // check the glyph's format, not the strike's format, and to be able to convert to any of the
diff --git a/src/gpu/GrFontScaler.h b/src/gpu/GrFontScaler.h
index 1dc5584c92..e42c7a1da0 100644
--- a/src/gpu/GrFontScaler.h
+++ b/src/gpu/GrFontScaler.h
@@ -52,7 +52,8 @@ public:
     GrMaskFormat getMaskFormat() const;
     GrMaskFormat getPackedGlyphMaskFormat(const SkGlyph&) const;
     bool getPackedGlyphBounds(const SkGlyph&, SkIRect* bounds);
-    bool getPackedGlyphImage(const SkGlyph&, int width, int height, int rowBytes, void* image);
+    bool getPackedGlyphImage(const SkGlyph&, int width, int height, int rowBytes,
+                             GrMaskFormat expectedMaskFormat, void* image);
     bool getPackedGlyphDFBounds(const SkGlyph&, SkIRect* bounds);
     bool getPackedGlyphDFImage(const SkGlyph&, int width, int height, void* image);
     const SkPath* getGlyphPath(const SkGlyph&);