Move GIF decoder's aggressive purge into ImageDecoder

third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h

 /*
  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) Research In Motion Limited 2009-2010. 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.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 259 matching lines @@
     }
 
     virtual bool canDecodeToYUV() { return false; }
     virtual bool decodeToYUV() { return false; }
     virtual void setImagePlanes(std::unique_ptr<ImagePlanes>) { }
 
 protected:
     ImageDecoder(AlphaOption alphaOption, GammaAndColorProfileOption colorOptions, size_t maxDecodedBytes)
         : m_premultiplyAlpha(alphaOption == AlphaPremultiplied)
         , m_ignoreGammaAndColorProfile(colorOptions == GammaAndColorProfileIgnored)
-        , m_maxDecodedBytes(maxDecodedBytes) { }
+        , m_maxDecodedBytes(maxDecodedBytes)
+        , m_purgeAggressively(false) { }
 
     // Calculates the most recent frame whose image data may be needed in
     // order to decode frame |frameIndex|, based on frame disposal methods
     // and |frameRectIsOpaque|, where |frameRectIsOpaque| signifies whether
     // the rectangle of frame at |frameIndex| is known to be opaque.
     // If no previous frame's data is required, returns WTF::kNotFound.
     //
     // This function requires that the previous frame's
     // |m_requiredPreviousFrameIndex| member has been set correctly. The
     // easiest way to ensure this is for subclasses to call this method and
@@ skipping 32 matching lines @@
     const bool m_ignoreGammaAndColorProfile;
     ImageOrientation m_orientation;
 
     // The maximum amount of memory a decoded image should require. Ideally,
     // image decoders should downsample large images to fit under this limit
     // (and then return the downsampled size from decodedSize()). Ignoring
     // this limit can cause excessive memory use or even crashes on low-
     // memory devices.
     const size_t m_maxDecodedBytes;
 
+    // While decoding, we may learn that there are so many animation frames that
+    // we would go beyond our cache budget.
+    // If that happens, m_purgeAggressively is set to true. This signals
+    // future decodes to purge old frames as it goes.
+    void updateAggressivePurging(size_t index);
+    bool m_purgeAggressively;
+
 private:
     enum class SniffResult {
         JPEG,
         PNG,
         GIF,
         WEBP,
         ICO,
         BMP,
         Invalid
     };
@@ skipping 18 matching lines @@
     ImageFrame::ICCProfile m_colorProfile;
 
 #if USE(QCMSLIB)
     QCMSTransformUniquePtr m_sourceToOutputDeviceColorTransform;
 #endif
 };
 
 } // namespace blink
 
 #endif