Improving canvas 2D performance by switching graphics rendering pipeline.

third_party/WebKit/Source/modules/canvas2d/BaseRenderingContext2D.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BaseRenderingContext2D_h
 #define BaseRenderingContext2D_h
 
 #include "bindings/modules/v8/HTMLImageElementOrHTMLVideoElementOrHTMLCanvasElementOrImageBitmap.h"
 #include "bindings/modules/v8/StringOrCanvasGradientOrCanvasPattern.h"
 #include "core/html/ImageData.h"
@@ skipping 170 matching lines @@
     enum DrawCallType {
         StrokePath = 0,
         FillPath,
         DrawImage,
         FillText,
         StrokeText,
         FillRect,
         StrokeRect
     };
 
-    const UsageCounters& getUsage();
+    virtual const UsageCounters& getUsage();

[Justin Novosad, 2016/07/14 18:07:10]

Why was this made virtual?

[sebastienlc, 2016/07/14 22:26:53]

Done.

 
 protected:
     BaseRenderingContext2D();
 
     CanvasRenderingContext2DState& modifiableState();
     const CanvasRenderingContext2DState& state() const { return *m_stateStack.last(); }
 
     bool computeDirtyRect(const FloatRect& localBounds, SkIRect*);
     bool computeDirtyRect(const FloatRect& localBounds, const SkIRect& transformedClipBounds, SkIRect*);
 
@@ skipping 117 matching lines @@
     foregroundPaint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
     c->setMatrix(ctm);
     drawFunc(c, &foregroundPaint);
     c->restore();
     c->setMatrix(ctm);
 }
 
 } // namespace blink
 
 #endif // BaseRenderingContext2D_h