memory coordinator: Add MemoryCoordinatorClient::OnPurgeMemory()

cc/resources/resource_pool.cc

 // Copyright 2012 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/resources/resource_pool.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 462 matching lines @@
     for (const auto& resource : busy_resources_) {
       resource->OnMemoryDump(pmd, resource_provider_, false /* is_free */);
     }
     for (const auto& entry : in_use_resources_) {
       entry.second->OnMemoryDump(pmd, resource_provider_, false /* is_free */);
     }
   }
   return true;
 }
 
-void ResourcePool::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:
-      // Release all resources, regardless of how recently they were used.
-      EvictResourcesNotUsedSince(base::TimeTicks() + base::TimeDelta::Max());
-      break;
-    case base::MemoryState::UNKNOWN:
-      // NOT_REACHED.
-      break;
-  }
+void ResourcePool::OnPurgeMemory() {
+  // Release all resources, regardless of how recently they were used.
+  EvictResourcesNotUsedSince(base::TimeTicks() + base::TimeDelta::Max());
 }
 
 }  // namespace cc