mus: Embedder can request and observe BeginFrame for embedded client.

ui/aura/test/mus/test_window_tree.cc

 // Copyright 2015 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 "ui/aura/test/mus/test_window_tree.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace aura {
 
@@ skipping 125 matching lines @@
 void TestWindowTree::SetWindowBounds(
     uint32_t change_id,
     uint32_t window_id,
     const gfx::Rect& bounds,
     const base::Optional<cc::LocalSurfaceId>& local_surface_id) {
   window_id_ = window_id;
   last_local_surface_id_ = local_surface_id;
   OnChangeReceived(change_id, WindowTreeChangeType::BOUNDS);
 }
 
+void TestWindowTree::RequestBeginFrames(
+    Id window_id,
+    cc::mojom::FrameSinkObserverPtr observer) {
+  NOTIMPLEMENTED();
+}
 void TestWindowTree::SetClientArea(
     uint32_t window_id,
     const gfx::Insets& insets,
     const base::Optional<std::vector<gfx::Rect>>& additional_client_areas) {
   last_client_area_ = insets;
 }
 
 void TestWindowTree::SetHitTestMask(uint32_t window_id,
                                     const base::Optional<gfx::Rect>& mask) {
   last_hit_test_mask_ = mask;
@@ skipping 150 matching lines @@
 void TestWindowTree::PerformWindowMove(uint32_t change_id,
                                        uint32_t window_id,
                                        ui::mojom::MoveLoopSource source,
                                        const gfx::Point& cursor_location) {
   OnChangeReceived(change_id);
 }
 
 void TestWindowTree::CancelWindowMove(uint32_t window_id) {}
 
 }  // namespace aura