Implement OnMemoryStateChange for Various CC Classes

cc/raster/staging_buffer_pool.cc

Index: cc/raster/staging_buffer_pool.cc
diff --git a/cc/raster/staging_buffer_pool.cc b/cc/raster/staging_buffer_pool.cc
index f55fd118fb87f4bb213398b5c4fe40be2ad1b286..8fec64c8370da83bb2e7b285cd71c3a7ab28b0c7 100644
--- a/cc/raster/staging_buffer_pool.cc
+++ b/cc/raster/staging_buffer_pool.cc
@@ -426,8 +426,8 @@ void StagingBufferPool::OnMemoryStateChange(base::MemoryState state) {
       // 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.