[SP] Allocate an SkPictureRecorder only once per GraphicsContext instantiation

Source/platform/graphics/GraphicsContext.h

 /*
  * Copyright (C) 2003, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008-2009 Torch Mobile, Inc.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 20 matching lines @@
 #include "platform/PlatformExport.h"
 #include "platform/fonts/Font.h"
 #include "platform/geometry/FloatRect.h"
 #include "platform/geometry/FloatRoundedRect.h"
 #include "platform/graphics/DashArray.h"
 #include "platform/graphics/DrawLooperBuilder.h"
 #include "platform/graphics/ImageOrientation.h"
 #include "platform/graphics/GraphicsContextAnnotation.h"
 #include "platform/graphics/GraphicsContextState.h"
 #include "platform/graphics/skia/SkiaUtils.h"
+#include "third_party/skia/include/core/SkPictureRecorder.h"
 #include "third_party/skia/include/core/SkRegion.h"
 #include "wtf/FastAllocBase.h"
 #include "wtf/Forward.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/PassOwnPtr.h"
 
 class SkBitmap;
 class SkImage;
 class SkPaint;
 class SkPath;
@@ skipping 366 matching lines @@
         }
     }
 
     void fillRectWithRoundedHole(const FloatRect&, const FloatRoundedRect& roundedHoleRect, const Color&);
 
     bool isRecording() const;
 
     // null indicates painting is contextDisabled. Never delete this object.
     SkCanvas* m_canvas;
 
+    // This stores the canvas object used to construct the GraphicsContext, if any. It is only
+    // used when Slimming Paint is active.
+    SkCanvas* m_originalCanvas;
+
     // This being null indicates not to paint into a DisplayItemList, and instead directly into the canvas.
     DisplayItemList* m_displayItemList;
 
     ClipRecorderStack* m_clipRecorderStack;
 
     // Paint states stack. Enables local drawing state change with save()/restore() calls.
     // This state controls the appearance of drawn content.
     // We do not delete from this stack to avoid memory churn.
     Vector<OwnPtr<GraphicsContextState>> m_paintStateStack;
     // Current index on the stack. May not be the last thing on the stack.
     unsigned m_paintStateIndex;
     // Raw pointer to the current state.
     GraphicsContextState* m_paintState;
 
     AnnotationModeFlags m_annotationMode;
 
+    // Only used when Slimming Paint is off. When it is on, m_pictureRecorder is used instead.
     Vector<OwnPtr<RecordingState>> m_recordingStateStack;
+    SkPictureRecorder m_pictureRecorder;
 
 #if ENABLE(ASSERT)
     unsigned m_layerCount;
     unsigned m_annotationCount;
     bool m_disableDestructionChecks;
     bool m_inDrawingRecorder;
 #endif
 
     const DisabledMode m_disabledState;
 
     float m_deviceScaleFactor;
 
     unsigned m_accelerated : 1;
     unsigned m_printing : 1;
     unsigned m_antialiasHairlineImages : 1;
 };
 
 } // namespace blink
 
 #endif // GraphicsContext_h