Clear Image Decode Cache on Navigation

cc/tiles/software_image_decode_cache.cc

Index: cc/tiles/software_image_decode_cache.cc
diff --git a/cc/tiles/software_image_decode_cache.cc b/cc/tiles/software_image_decode_cache.cc
index a113be9dd198ca6faeb12bb6092c98033554cea9..c40e5561bbd40c35efd77fab9d421e01f068a2a3 100644
--- a/cc/tiles/software_image_decode_cache.cc
+++ b/cc/tiles/software_image_decode_cache.cc
@@ -818,6 +818,11 @@ void SoftwareImageDecodeCache::ReduceCacheUsage() {
   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_);