While dragging a window, show a semi-transparent aura window instead of the standard gray phantom wi

ash/wm/workspace/frame_maximize_button.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/workspace/frame_maximize_button.h"
 
 #include "ash/launcher/launcher.h"
 #include "ash/screen_ash.h"
 #include "ash/shell.h"
 #include "ash/wm/property_util.h"
@@ skipping 370 matching lines @@
   if (snap_type_ == SNAP_LEFT || snap_type_ == SNAP_RIGHT) {
     SnapSizer::Edge snap_edge = snap_type_ == SNAP_LEFT ?
         SnapSizer::LEFT_EDGE : SnapSizer::RIGHT_EDGE;
     int grid_size = Shell::GetInstance()->GetGridSize();
     snap_sizer_.reset(new SnapSizer(frame_->GetWidget()->GetNativeWindow(),
                                     LocationForSnapSizer(location),
                                     snap_edge, grid_size));
   }
   if (!phantom_window_.get()) {
     phantom_window_.reset(new internal::PhantomWindowController(
-                              frame_->GetWidget()->GetNativeWindow()));
+        frame_->GetWidget()->GetNativeWindow(),
+        NULL,
+        internal::PhantomWindowController::STYLE_SHADOW));
   }
   if (maximizer_.get()) {
     phantom_window_->set_phantom_below_window(maximizer_->GetBubbleWindow());
     maximizer_->SetSnapType(snap_type_);
   }
   phantom_window_->Show(ScreenBoundsForType(snap_type_));
 }
 
 SnapType FrameMaximizeButton::SnapTypeForLocation(
     const gfx::Point& location) const {
@@ skipping 71 matching lines @@
       break;
     case SNAP_RESTORE:
       frame_->GetWidget()->Restore();
       break;
     case SNAP_NONE:
       NOTREACHED();
   }
 }
 
 }  // namespace ash