Clear Image Decode Cache on Navigation

cc/tiles/software_image_decode_cache.cc

 // 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.
 
 #include "cc/tiles/software_image_decode_cache.h"
 
 #include <inttypes.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 800 matching lines @@
     it = decoded_images_.Erase(it);
     --num_to_remove;
   }
 }
 
 void SoftwareImageDecodeCache::ReduceCacheUsage() {
   base::AutoLock lock(lock_);
   ReduceCacheUsageUntilWithinLimit(max_items_in_cache_);
 }
 
+void SoftwareImageDecodeCache::ClearCache() {
+  base::AutoLock lock(lock_);
+  ReduceCacheUsageUntilWithinLimit(0);
+}
+
 void SoftwareImageDecodeCache::RemovePendingTask(const ImageKey& key,
                                                  DecodeTaskType task_type) {
   base::AutoLock lock(lock_);
   switch (task_type) {
     case DecodeTaskType::USE_IN_RASTER_TASKS:
       pending_in_raster_image_tasks_.erase(key);
       break;
     case DecodeTaskType::USE_OUT_OF_RASTER_TASKS:
       pending_out_of_raster_image_tasks_.erase(key);
       break;
@@ skipping 346 matching lines @@
     }
   }
 }
 
 void SoftwareImageDecodeCache::OnPurgeMemory() {
   base::AutoLock lock(lock_);
   ReduceCacheUsageUntilWithinLimit(0);
 }
 
 }  // namespace cc