gpu: Use mojom API for getting video memory usage.

gpu/ipc/common/memory_stats.mojom

Index: gpu/ipc/common/memory_stats.mojom
diff --git a/gpu/ipc/common/memory_stats.mojom b/gpu/ipc/common/memory_stats.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..4fe8825bb61cffbdaf3ea47f81d9f400bb0f2aef
--- /dev/null
+++ b/gpu/ipc/common/memory_stats.mojom
@@ -0,0 +1,15 @@
+// Copyright 2017 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.
+
+module gpu.mojom;
+
+struct VideoMemoryProcessStats {
+  uint64 video_memory_bytes;
+  bool has_duplicates;
+};
+
+struct VideoMemoryUsageStats {
+  map<int32, VideoMemoryProcessStats> process_map;
+  uint64 bytes_allocated;
+};