Clear Image Decode Cache on Navigation

cc/tiles/software_image_decode_cache.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_TILES_SOFTWARE_IMAGE_DECODE_CACHE_H_
 #define CC_TILES_SOFTWARE_IMAGE_DECODE_CACHE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 112 matching lines @@
       const DrawImage& image,
       scoped_refptr<TileTask>* task) override;
   void UnrefImage(const DrawImage& image) override;
   DecodedDrawImage GetDecodedImageForDraw(const DrawImage& image) override;
   void DrawWithImageFinished(const DrawImage& image,
                              const DecodedDrawImage& decoded_image) override;
   void ReduceCacheUsage() override;
   // Software doesn't keep outstanding images pinned, so this is a no-op.
   void SetShouldAggressivelyFreeResources(
       bool aggressively_free_resources) override {}
+  void ClearCache() override;
 
   // Decode the given image and store it in the cache. This is only called by an
   // image decode task from a worker thread.
   void DecodeImage(const ImageKey& key,
                    const DrawImage& image,
                    DecodeTaskType task_type);
 
   void RemovePendingTask(const ImageKey& key, DecodeTaskType task_type);
 
   // MemoryDumpProvider overrides.
@@ skipping 166 matching lines @@
   ResourceFormat format_;
   size_t max_items_in_cache_;
 
   // Used to uniquely identify DecodedImages for memory traces.
   base::AtomicSequenceNumber next_tracing_id_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TILES_SOFTWARE_IMAGE_DECODE_CACHE_H_