Make panels turn on or off shadow effect.

chrome/browser/ui/panels/stacked_panel_collection.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 "chrome/browser/ui/panels/stacked_panel_collection.h"
 
 #include <algorithm>
 #include "base/auto_reset.h"
 #include "base/logging.h"
 #include "chrome/browser/ui/panels/detached_panel_collection.h"
@@ skipping 504 matching lines @@
 
 bool StackedPanelCollection::HasPanel(Panel* panel) const {
   return std::find(panels_.begin(), panels_.end(), panel) != panels_.end();
 }
 
 void StackedPanelCollection::UpdatePanelOnCollectionChange(Panel* panel) {
   panel->set_attention_mode(
       static_cast<Panel::AttentionMode>(Panel::USE_PANEL_ATTENTION |
                                         Panel::USE_SYSTEM_ATTENTION));
   panel->SetAlwaysOnTop(false);
+  // TODO(jianli): Change from true to false when the background window is used
+  // to provide the shadow.
+  panel->ShowShadow(true);
   panel->EnableResizeByMouse(true);
   panel->UpdateMinimizeRestoreButtonVisibility();
   UpdatePanelCornerStyle(panel);
 }
 
 void StackedPanelCollection::OnPanelExpansionStateChanged(Panel* panel) {
   DCHECK_NE(Panel::MINIMIZED, panel->expansion_state());
 
   gfx::Rect bounds = panel->GetBounds();
   bounds.set_height(panel->expansion_state() == Panel::EXPANDED ?
@@ skipping 123 matching lines @@
     if (panel->IsActive())
       bottom += panel->GetBounds().height();
     else
       bottom += panel::kTitlebarHeight;
   }
   int available_space = work_area.bottom() - bottom;
   if (available_space < 0)
     available_space = 0;
   return available_space;
 }