Add display list fallback reason histograms for 2D canvas

third_party/WebKit/Source/core/html/HTMLCanvasElement.h

Index: third_party/WebKit/Source/core/html/HTMLCanvasElement.h
diff --git a/third_party/WebKit/Source/core/html/HTMLCanvasElement.h b/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
index 55ef7bb14f877ac2202ad5f72110a1edd023e397..75fdf3c7ce4a3a065be28f9c1e1b99cf2cb524f1 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
@@ -114,7 +114,7 @@ public:
     void paint(GraphicsContext&, const LayoutRect&);
 
     SkCanvas* drawingCanvas() const;
-    void disableDeferral() const;
+    void disableDeferral(DisableDeferralReason) const;
     SkCanvas* existingDrawingCanvas() const;
 
     void setRenderingContext(PassOwnPtrWillBeRawPtr<CanvasRenderingContext>);
@@ -152,7 +152,7 @@ public:
     void willDetachDocument() override;
 
     // CanvasImageSource implementation
-    PassRefPtr<Image> getSourceImageForCanvas(SourceImageStatus*, AccelerationHint) const override;
+    PassRefPtr<Image> getSourceImageForCanvas(SourceImageStatus*, AccelerationHint, SnapshotReason) const override;
     bool wouldTaintOrigin(SecurityOrigin*) const override;
     FloatSize elementSize() const override;
     bool isCanvasElement() const override { return true; }
@@ -207,7 +207,8 @@ private:
 
     bool paintsIntoCanvasBuffer() const;
 
-    ImageData* toImageData(SourceDrawingBuffer) const;
+    ImageData* toImageData(SourceDrawingBuffer, SnapshotReason) const;
+
     String toDataURLInternal(const String& mimeType, const double& quality, SourceDrawingBuffer) const;
 
     PersistentHeapHashSetWillBeHeapHashSet<WeakMember<CanvasDrawListener>> m_listeners;