[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 31 matching lines @@
 #include "wtf/FastAllocBase.h"
 #include "wtf/Forward.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/PassOwnPtr.h"
 
 class SkBitmap;
 class SkImage;
 class SkPaint;
 class SkPath;
 class SkPicture;
+class SkPictureRecorder;
 class SkRRect;
 class SkTextBlob;
 struct SkImageInfo;
 struct SkRect;
 
 namespace blink {
 
 class ClipRecorderStack;
 class DisplayItemList;
 class ImageBuffer;
@@ skipping 371 matching lines @@
     // 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;
+    OwnPtr<SkPictureRecorder> m_pictureRecorder;

[f(malita), 2015/04/13 21:39:45]

This has the same lifetime as GC - can we drop the OwnPtr wrapper and just store
a straight SkPictureRecorder instead?

[chrishtr, 2015/04/13 21:48:34]

Done.

 
 #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