Implement OnMemoryStateChange for Various CC Classes

cc/raster/staging_buffer_pool.cc

 // 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.
 
 #include "cc/raster/staging_buffer_pool.h"
 
 #include <memory>
 
 #include "base/memory/memory_coordinator_client_registry.h"
 #include "base/memory/ptr_util.h"
@@ skipping 408 matching lines @@
 void StagingBufferPool::OnMemoryStateChange(base::MemoryState state) {
   switch (state) {
     case base::MemoryState::NORMAL:
       // TODO(tasak): go back to normal state.
       break;
     case base::MemoryState::THROTTLED:
       // TODO(tasak): make the limits of this component's caches smaller to
       // save memory usage.
       break;
     case base::MemoryState::SUSPENDED:
-      // TODO(tasak): free this component's caches as much as possible before
-      // suspending renderer.
+      // Release all buffers, regardless of how recently they were used.
+      ReleaseBuffersNotUsedSince(base::TimeTicks() + base::TimeDelta::Max());
       break;
     case base::MemoryState::UNKNOWN:
       // NOT_REACHED.
       break;
   }
 }
 
 }  // namespace cc