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 261 matching lines @@
   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 };
 
   static SniffResult determineImageType(const char* data, size_t length);
 
   // Some code paths compute the size of the image as "width * height * 4"
   // and return it as a (signed) int.  Avoid overflow.
   static bool sizeCalculationMayOverflow(unsigned width, unsigned height) {
     unsigned long long total_size = static_cast<unsigned long long>(width) *
                                     static_cast<unsigned long long>(height);
     return total_size > ((1 << 29) - 1);
   }
 
   IntSize m_size;
   bool m_sizeAvailable = false;
   bool m_isAllDataReceived = false;
   bool m_failed = false;
 
   bool m_hasColorProfile = false;
   ImageFrame::ICCProfile m_colorProfile;
 
 #if USE(QCMSLIB)
   QCMSTransformUniquePtr m_sourceToOutputDeviceColorTransform;
 #endif
 };
 
 }  // namespace blink
 
 #endif