Implement cc::BeginFrameArgs StructTraits

cc/ipc/begin_frame_args.mojom

+// 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.
+
+module cc.mojom;
+
+import "mojo/common/common_custom_types.mojom";
+
+enum BeginFrameArgsType {
+  INVALID,
+  NORMAL,
+  MISSED,
+  BEGIN_FRAME_ARGS_TYPE_MAX
+};
+
+// See cc/output/begin_frame_args.h.
+struct BeginFrameArgs {
+  mojo.common.mojom.TimeTicks frame_time;
+  mojo.common.mojom.TimeTicks deadline;
+  mojo.common.mojom.TimeDelta interval;
+  BeginFrameArgsType type;
+  bool on_critical_path;
+};