(Merge to M-51) Revise the shelf alignment locking mechanism.

ash/wm/panels/panel_window_resizer.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/panels/panel_window_resizer.h"
 
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/screen_util.h"
 #include "ash/shelf/shelf.h"
 #include "ash/shelf/shelf_types.h"
@@ skipping 122 matching lines @@
   bool should_attach = false;
   if (panel_container_) {
     PanelLayoutManager* panel_layout_manager =
         GetPanelLayoutManager(panel_container_);
     gfx::Rect launcher_bounds = ScreenUtil::ConvertRectFromScreen(
         GetTarget()->parent(),
         panel_layout_manager->shelf()->
         shelf_widget()->GetWindowBoundsInScreen());
     switch (panel_layout_manager->shelf()->alignment()) {
       case SHELF_ALIGNMENT_BOTTOM:
+      case SHELF_ALIGNMENT_BOTTOM_LOCKED:
         if (bounds.bottom() >= (launcher_bounds.y() -
                                 kPanelSnapToLauncherDistance)) {
           should_attach = true;
           offset->set_y(launcher_bounds.y() - bounds.height() - bounds.y());
         }
         break;
       case SHELF_ALIGNMENT_LEFT:
         if (bounds.x() <= (launcher_bounds.right() +
                            kPanelSnapToLauncherDistance)) {
           should_attach = true;
@@ skipping 56 matching lines @@
 }
 
 void PanelWindowResizer::UpdateLauncherPosition() {
   if (panel_container_) {
     GetPanelLayoutManager(panel_container_)->shelf()->
         UpdateIconPositionForWindow(GetTarget());
   }
 }
 
 }  // namespace aura