Mozart: Generalize frame scheduling.

services/gfx/compositor/frame_dispatcher.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 "services/gfx/compositor/frame_dispatcher.h"
+
+namespace compositor {
+
+FrameDispatcher::FrameDispatcher() {}
+
+FrameDispatcher::~FrameDispatcher() {}
+
+bool FrameDispatcher::AddCallback(const FrameCallback& callback) {
+  pending_callbacks_.emplace_back(callback);
+  return pending_callbacks_.size() == 1u;
+}
+
+void FrameDispatcher::DispatchCallbacks(
+    const mojo::gfx::composition::FrameInfo& frame_info) {
+  for (auto& callback : pending_callbacks_) {
+    callback.Run(frame_info.Clone());
+  }
+  pending_callbacks_.clear();
+}
+
+}  // namespace compositor