[WIP] cc: Plumb SurfaceId from clients

ash/wm/window_animations.cc

 // Copyright (c) 2012 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/wm/window_animations.h"
 
 #include <math.h>
 #include <algorithm>
 #include <utility>
 #include <vector>
@@ skipping 260 matching lines @@
     window_->AddObserver(this);
     layer_owner_->root()->GetCompositor()->AddObserver(this);
   }
   ~CrossFadeObserver() override {
     window_->RemoveObserver(this);
     window_ = NULL;
     layer_owner_->root()->GetCompositor()->RemoveObserver(this);
   }
 
   // ui::CompositorObserver overrides:
+  void OnCompositingInitialized(ui::Compositor* compositor) override {}
   void OnCompositingDidCommit(ui::Compositor* compositor) override {}
   void OnCompositingStarted(ui::Compositor* compositor,
                             base::TimeTicks start_time) override {}
   void OnCompositingEnded(ui::Compositor* compositor) override {}
   void OnCompositingAborted(ui::Compositor* compositor) override {
     // Triggers OnImplicitAnimationsCompleted() to be called and deletes us.
     layer_owner_->root()->GetAnimator()->StopAnimating();
   }
   void OnCompositingLockStateChanged(ui::Compositor* compositor) override {}
   void OnCompositingShuttingDown(ui::Compositor* compositor) override {}
@@ skipping 191 matching lines @@
   gfx::Rect work_area =
       display::Screen::GetScreen()->GetDisplayNearestWindow(window).work_area();
   int ltr_adjusted_x = base::i18n::IsRTL() ? work_area.right() : work_area.x();
   return shelf->SelectValueForShelfAlignment(
       gfx::Rect(ltr_adjusted_x, work_area.bottom(), 0, 0),
       gfx::Rect(work_area.x(), work_area.y(), 0, 0),
       gfx::Rect(work_area.right(), work_area.y(), 0, 0));
 }
 
 }  // namespace ash