Prevent synchronous layout while painting the last frame of a gif

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

 /*
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2004, 2005, 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2008-2009 Torch Mobile, Inc.
  *
  * 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 72 matching lines @@
 
     bool currentFrameKnownToBeOpaque(MetadataMode = UseCurrentMetadata) override;
     bool currentFrameIsComplete() override;
     bool currentFrameIsLazyDecoded() override;
 
     ImageOrientation currentFrameOrientation();
 
     // Construct a BitmapImage with the given orientation.
     static PassRefPtr<BitmapImage> createWithOrientationForTesting(const SkBitmap&, ImageOrientation);
     // Advance the image animation by one frame.
-    void advanceAnimationForTesting() override { internalAdvanceAnimation(false); }
+    void advanceAnimationForTesting() override { internalAdvanceAnimation(); }
 
 private:
     enum RepetitionCountStatus {
       Unknown,    // We haven't checked the source's repetition count.
       Uncertain,  // We have a repetition count, but it might be wrong (some GIFs have a count after the image data, and will report "loop once" until all data has been decoded).
       Certain     // The repetition count is known to be correct.
     };
 
     BitmapImage(const SkBitmap &, ImageObserver* = 0);
     BitmapImage(ImageObserver* = 0);
@@ skipping 39 matching lines @@
     void startAnimation(CatchUpAnimation = CatchUp) override;
     void stopAnimation();
     void advanceAnimation(TimerBase*);
     // Advance the animation and let the next frame get scheduled without
     // catch-up logic. For large images with slow or heavily-loaded systems,
     // throwing away data as we go (see destroyDecodedData()) means we can spend
     // so much time re-decoding data that we are always behind. To prevent this,
     // we force the next animation to skip the catch up logic.
     void advanceAnimationWithoutCatchUp(TimerBase*);
 
-    // Function that does the real work of advancing the animation.  When
-    // skippingFrames is true, we're in the middle of a loop trying to skip over
-    // a bunch of animation frames, so we should not do things like decode each
-    // one or notify our observers.
+    // This function does the real work of advancing the animation. When
+    // skipping frames to catch up, we're in the middle of a loop trying to skip
+    // over a bunch of animation frames, so we should not do things like decode
+    // each one or notify our observers.
     // Returns whether the animation was advanced.
-    bool internalAdvanceAnimation(bool skippingFrames);
+    enum AnimationAdvancement {
+        Normal,
+        SkipFramesToCatchUp
+    };
+    bool internalAdvanceAnimation(AnimationAdvancement = Normal);
+
+    void notifyObserversOfAnimationAdvance(TimerBase*);
 
     ImageSource m_source;
     mutable IntSize m_size; // The size to use for the overall image (will just be the size of the first image).
     mutable IntSize m_sizeRespectingOrientation;
 
     size_t m_currentFrame; // The index of the current frame of animation.
     Vector<FrameData, 1> m_frames; // An array of the cached frames of the animation. We have to ref frames to pin them in the cache.
 
     RefPtr<SkImage> m_cachedFrame; // A cached copy of the most recently-accessed frame.
     size_t m_cachedFrameIndex; // Index of the frame that is cached.
@@ skipping 14 matching lines @@
     mutable bool m_haveSize : 1; // Whether or not our |m_size| member variable has the final overall image size yet.
     bool m_sizeAvailable : 1; // Whether or not we can obtain the size of the first image frame yet from ImageIO.
     mutable bool m_haveFrameCount : 1;
 };
 
 DEFINE_IMAGE_TYPE_CASTS(BitmapImage);
 
 } // namespace blink
 
 #endif