Extract the code of showing a dragging window on another display from PhantomWindowController.

ash/wm/gestures/system_pinch_handler.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/gestures/system_pinch_handler.h"
 
 #include "ash/launcher/launcher.h"
 #include "ash/screen_ash.h"
 #include "ash/shell.h"
 #include "ash/wm/property_util.h"
@@ skipping 55 matching lines @@
       }
       return SYSTEM_GESTURE_END;
     }
 
     case ui::ET_GESTURE_PINCH_UPDATE: {
       // The PINCH_UPDATE events contain incremental scaling updates.
       pinch_factor_ *= event.details().scale();
       gfx::Rect bounds =
           GetPhantomWindowScreenBounds(target_, event.location());
       if (phantom_state_ != PHANTOM_WINDOW_NORMAL || phantom_.IsShowing())
-        phantom_.Show(bounds, NULL);
+        phantom_.Show(bounds);
       break;
     }
 
     case ui::ET_GESTURE_MULTIFINGER_SWIPE: {
       phantom_.Hide();
       pinch_factor_ = 1.0;
       phantom_state_ = PHANTOM_WINDOW_NORMAL;
 
       if (event.details().swipe_left() || event.details().swipe_right()) {
         // Snap for left/right swipes.
@@ skipping 50 matching lines @@
     phantom_state_ = PHANTOM_WINDOW_MINIMIZED;
     return rect;
   }
 
   phantom_state_ = PHANTOM_WINDOW_NORMAL;
   return window->bounds();
 }
 
 }  // namespace internal
 }  // namespace ash