Animating docked background in sync with shelf

ash/shelf/shelf_layout_manager.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/shelf/shelf_layout_manager.h"
 
 #include <algorithm>
 #include <cmath>
 #include <cstring>
 #include <string>
@@ skipping 913 matching lines @@
       status_x.set_x(0);
       status_x.ClampToCenteredSize(
           target_bounds->status_bounds_in_shelf.size());
       target_bounds->status_bounds_in_shelf.set_x(status_x.x());
     }
   }
 }
 
 void ShelfLayoutManager::UpdateShelfBackground(
     BackgroundAnimator::ChangeType type) {
-  shelf_->SetPaintsBackground(GetShelfBackgroundType(), type);
+  const ShelfBackgroundType background_type(GetShelfBackgroundType());
+  shelf_->SetPaintsBackground(background_type, type);
+  FOR_EACH_OBSERVER(ShelfLayoutManagerObserver, observers_,
+                    OnBackgroundUpdated(background_type, type));
 }
 
 ShelfBackgroundType ShelfLayoutManager::GetShelfBackgroundType() const {
   if (state_.visibility_state != SHELF_AUTO_HIDE &&
       state_.window_state == WORKSPACE_WINDOW_STATE_MAXIMIZED) {
     return SHELF_BACKGROUND_MAXIMIZED;
   }
 
   if (gesture_drag_status_ == GESTURE_DRAG_IN_PROGRESS ||
       (!state_.is_screen_locked && window_overlaps_shelf_) ||
@@ skipping 213 matching lines @@
       return gfx::Insets(0, distance, 0, 0);
     case SHELF_ALIGNMENT_TOP:
       return gfx::Insets(0, 0, distance, 0);
   }
   NOTREACHED();
   return gfx::Insets();
 }
 
 }  // namespace internal
 }  // namespace ash