Add display list fallback reason histograms for 2D canvas

third_party/WebKit/Source/platform/graphics/RecordingImageBufferSurface.h

 // Copyright 2014 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 RecordingImageBufferSurface_h
 #define RecordingImageBufferSurface_h
 
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/ImageBufferSurface.h"
 #include "public/platform/WebThread.h"
@@ skipping 22 matching lines @@
 };
 
 class PLATFORM_EXPORT RecordingImageBufferSurface : public ImageBufferSurface {
     WTF_MAKE_NONCOPYABLE(RecordingImageBufferSurface); USING_FAST_MALLOC(RecordingImageBufferSurface);
 public:
     RecordingImageBufferSurface(const IntSize&, PassOwnPtr<RecordingImageBufferFallbackSurfaceFactory> fallbackFactory, OpacityMode = NonOpaque);
     ~RecordingImageBufferSurface() override;
 
     // Implementation of ImageBufferSurface interfaces
     SkCanvas* canvas() override;
-    void disableDeferral() override;
+    void disableDeferral(DisableDeferralReason) override;
     PassRefPtr<SkPicture> getPicture() override;
-    void flush() override;
+    void flush(FlushReason) override;
     void didDraw(const FloatRect&) override;
     bool isValid() const override { return true; }
     bool isRecording() const override { return !m_fallbackSurface; }
     bool writePixels(const SkImageInfo& origInfo, const void* pixels, size_t rowBytes, int x, int y) override;
     void willOverwriteCanvas() override;
     virtual void finalizeFrame(const FloatRect&);
     void setImageBuffer(ImageBuffer*) override;
-    PassRefPtr<SkImage> newImageSnapshot(AccelerationHint) override;
+    PassRefPtr<SkImage> newImageSnapshot(AccelerationHint, SnapshotReason) override;
     void draw(GraphicsContext&, const FloatRect& destRect, const FloatRect& srcRect, SkXfermode::Mode) override;
     bool isExpensiveToPaint() override;
     void setHasExpensiveOp() override { m_currentFrameHasExpensiveOp = true; }
 
     // Passthroughs to fallback surface
     bool restore() override;
     WebLayer* layer() const override;
     bool isAccelerated() const override;
     void setIsHidden(bool) override;
 
+    enum FallbackReason {
+        FallbackReasonUnknown = 0, // This value should never appear in production histograms
+        FallbackReasonCanvasNotClearedBetweenFrames = 1,
+        FallbackReasonRunawayStateStack = 2,
+        FallbackReasonWritePixels = 3,
+        FallbackReasonFlushInitialClear = 4,
+        FallbackReasonFlushForDrawImageOfWebGL = 5,
+        FallbackReasonSnapshotForGetImageData = 6,
+        FallbackReasonSnapshotForCopyToWebGLTexture = 7,
+        FallbackReasonSnapshotForPaint = 8,
+        FallbackReasonSnapshotForToDataURL = 9,
+        FallbackReasonSnapshotForToBlob = 10,
+        FallbackReasonSnapshotForCanvasListenerCapture = 11,
+        FallbackReasonSnapshotForDrawImage = 12,
+        FallbackReasonSnapshotForCreatePattern = 13,
+        FallbackReasonExpensiveOverdrawHeuristic = 14,
+        FallbackReasonTextureBackedPattern = 15,
+        FallbackReasonDrawImageOfVideo = 16,
+        FallbackReasonDrawImageOfAnimated2dCanvas = 17,
+        FallbackReasonSubPixelTextAntiAliasingSupport = 18,
+        FallbackReasonCount,
+    };
 private:
     friend class RecordingImageBufferSurfaceTest; // for unit testing
-    void fallBackToRasterCanvas();
-    bool initializeCurrentFrame();
-    bool finalizeFrameInternal();
+    void fallBackToRasterCanvas(FallbackReason);
+    void initializeCurrentFrame();
+    bool finalizeFrameInternal(FallbackReason*);
     int approximateOpCount();
 
     OwnPtr<SkPictureRecorder> m_currentFrame;
     RefPtr<SkPicture> m_previousFrame;
     OwnPtr<ImageBufferSurface> m_fallbackSurface;
     ImageBuffer* m_imageBuffer;
     int m_initialSaveCount;
     int m_currentFramePixelCount;
     int m_previousFramePixelCount;
     bool m_frameWasCleared;
     bool m_didRecordDrawCommandsInCurrentFrame;
     bool m_currentFrameHasExpensiveOp;
     bool m_previousFrameHasExpensiveOp;
     OwnPtr<RecordingImageBufferFallbackSurfaceFactory> m_fallbackFactory;
 };
 
 } // namespace blink
 
 #endif