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

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 9a70b4f98a14d6b7907260b70c1bb85aaa2da985..83b70264877728d8aa0d0e33ad98741876d8b812 100644
--- a/cc/tiles/software_image_decode_cache.cc
+++ b/cc/tiles/software_image_decode_cache.cc
@@ -856,6 +856,10 @@ size_t SoftwareImageDecodeCache::GetMaximumMemoryLimitBytes() const {
   return locked_images_budget_.total_limit_bytes();
 }
 
+void SoftwareImageDecodeCache::NotifyImageUnused(uint32_t skimage_id) {
+  // TODO(sohanjg) :Implement it, crbug.com/734982.
+}
+
 void SoftwareImageDecodeCache::RemovePendingTask(const ImageKey& key,
                                                  DecodeTaskType task_type) {
   base::AutoLock lock(lock_);