Fix app list search box rendering above app list overlay.

ui/app_list/views/app_list_view.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 "ui/app_list/views/app_list_view.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
@@ skipping 258 matching lines @@
     animation_observer_->SetTarget(overlay_view_);
     settings.AddObserver(animation_observer_.get());
   }
 
   const float kOverlayFadeInMilliseconds = 125;
   settings.SetTransitionDuration(
       base::TimeDelta::FromMilliseconds(kOverlayFadeInMilliseconds));
 
   const float kOverlayOpacity = 0.75f;
   overlay_view_->layer()->SetOpacity(visible ? kOverlayOpacity : 0.0f);
+  // Create the illusion that the search box is hidden behind the app list
+  // overlay mask by setting its opacity to the same value, and disabling it.
+  {
+    ui::ScopedLayerAnimationSettings settings(
+        search_box_widget_->GetLayer()->GetAnimator());
+    const float kSearchBoxWidgetOpacity = 0.5f;
+    search_box_widget_->GetLayer()->SetOpacity(visible ? kSearchBoxWidgetOpacity
+                                                       : 1.0f);
+    search_box_view_->SetEnabled(!visible);
+  }
 }
 
 bool AppListView::ShouldCenterWindow() const {
   return delegate_->ShouldCenterWindow();
 }
 
 gfx::Size AppListView::GetPreferredSize() const {
   return app_list_main_view_->GetPreferredSize();
 }
 
@@ skipping 404 matching lines @@
 
   if (will_appear) {
     speech_view_->SetVisible(true);
   } else {
     app_list_main_view_->SetVisible(true);
     search_box_view_->search_box()->RequestFocus();
   }
 }
 
 }  // namespace app_list