cc: Interface to evict images from cc image decode cache.

cc/tiles/image_decode_cache.h

 // Copyright 2015 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_IMAGE_DECODE_CACHE_H_
 #define CC_TILES_IMAGE_DECODE_CACHE_H_
 
 #include "base/memory/ref_counted.h"
 #include "cc/base/devtools_instrumentation.h"
 #include "cc/paint/draw_image.h"
@@ skipping 106 matching lines @@
       bool aggressively_free_resources) = 0;
 
   // Clears all elements from the cache.
   virtual void ClearCache() = 0;
 
   // Returns the maximum amount of memory we would be able to lock. This ignores
   // any temporary states, such as throttled, and return the maximum possible
   // memory. It is used as an esimate of whether an image can fit into the
   // locked budget before creating a task.
   virtual size_t GetMaximumMemoryLimitBytes() const = 0;
+
+  // Indicate to the cache that the image is no longer going
+  // to be used. This means it can be deleted altogether. If the
+  // image is locked, then the cache can do its best to clean it
+  // up later.
+  virtual void NotifyImageUnused(uint32_t skimage_id) = 0;
 };
 
 }  // namespace cc
 
 #endif  // CC_TILES_IMAGE_DECODE_CACHE_H_