Revert of Remove CompositorObserver::OnCompositingEnded()

ash/mus/non_client_frame_controller_unittest.cc

 // 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.
 
 #include "ash/mus/non_client_frame_controller.h"
 
 #include "ash/ash_layout_constants.h"
 #include "ash/mus/top_level_window_factory.h"
 #include "ash/mus/window_manager_application.h"
 #include "ash/test/ash_test_base.h"
@@ skipping 102 matching lines @@
   const int tile_height = tile_size.height();
   const int tile_x = tile_width;
   const int tile_y = tile_height;
 
   const gfx::Rect kTileBounds(gfx::Point(tile_x, tile_y), tile_size);
   ui::Compositor* compositor = widget->GetCompositor();
 
   // Without the window visible, there should be a tile for the wallpaper at
   // (tile_x, tile_y) of size |tile_size|.
   compositor->ScheduleDraw();
-  ui::DrawWaiterForTest::WaitForCompositingStarted(compositor);
+  ui::DrawWaiterForTest::WaitForCompositingEnded(compositor);
   {
     const cc::CompositorFrame& frame = GetLastCompositorFrame();
     ASSERT_EQ(1u, frame.render_pass_list.size());
     EXPECT_TRUE(FindColorQuad(frame, kTileBounds, SK_ColorBLACK));
   }
 
   // Show |widget|, and position it so that it covers that wallpaper tile.
   const gfx::Rect widget_bound(tile_x - 10, tile_y - 10, tile_width + 20,
                                tile_height + 20);
   widget->SetBounds(widget_bound);
   widget->Show();
   compositor->ScheduleDraw();
-  ui::DrawWaiterForTest::WaitForCompositingStarted(compositor);
+  ui::DrawWaiterForTest::WaitForCompositingEnded(compositor);
   {
     // This time, that tile for the wallpaper will not be drawn.
     const cc::CompositorFrame& frame = GetLastCompositorFrame();
     ASSERT_EQ(1u, frame.render_pass_list.size());
     EXPECT_FALSE(FindColorQuad(frame, kTileBounds, SK_ColorBLACK));
 
     // Instead, there will be some solid-color quads for the widget.
     const gfx::Rect top_left(widget_bound.origin(), tile_size);
     const gfx::Rect top_right(
         top_left.top_right(),
@@ skipping 11 matching lines @@
 
     // And there will be a content quad for the window caption.
     gfx::Rect caption_bound(widget_bound);
     caption_bound.set_height(caption_height);
     EXPECT_TRUE(FindTiledContentQuad(frame, caption_bound));
   }
 }
 
 }  // namespace mus
 }  // namespace ash