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

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/maximize_bubble_controller.h"
@@ skipping 367 matching lines @@
 
 void FrameMaximizeButton::UpdateSnap(const gfx::Point& location,
                                      bool select_default,
                                      bool is_touch) {
   SnapType type = SnapTypeForLocation(location);
   if (type == snap_type_) {
     if (snap_sizer_.get()) {
       snap_sizer_->Update(LocationForSnapSizer(location));
       phantom_window_->Show(ScreenAsh::ConvertRectToScreen(
           frame_->GetWidget()->GetNativeView()->parent(),
-          snap_sizer_->target_bounds()), NULL);
+          snap_sizer_->target_bounds()));
     }
     return;
   }
 
   snap_type_ = type;
   snap_sizer_.reset();
   SchedulePaint();
 
   if (snap_type_ == SNAP_NONE) {
     phantom_window_.reset();
@@ skipping 15 matching lines @@
   }
   if (!phantom_window_.get()) {
     phantom_window_.reset(new internal::PhantomWindowController(
                               frame_->GetWidget()->GetNativeWindow()));
   }
   if (maximizer_.get()) {
     phantom_window_->set_phantom_below_window(maximizer_->GetBubbleWindow());
     maximizer_->SetSnapType(snap_type_);
   }
   phantom_window_->Show(
-      ScreenBoundsForType(snap_type_, *snap_sizer_.get()), NULL);
+      ScreenBoundsForType(snap_type_, *snap_sizer_.get()));
 }
 
 SnapType FrameMaximizeButton::SnapTypeForLocation(
     const gfx::Point& location) const {
   MaximizeBubbleFrameState maximize_type = GetMaximizeBubbleFrameState();
   gfx::Vector2d delta(location - press_location_);
   if (!views::View::ExceededDragThreshold(delta))
     return maximize_type != FRAME_STATE_FULL ? SNAP_MAXIMIZE : SNAP_RESTORE;
   if (delta.x() < 0 && delta.y() > delta.x() && delta.y() < -delta.x())
     return maximize_type == FRAME_STATE_SNAP_LEFT ? SNAP_RESTORE : SNAP_LEFT;
@@ skipping 119 matching lines @@
     return FRAME_STATE_SNAP_LEFT;
   if (bounds.right() == screen.right())
     return FRAME_STATE_SNAP_RIGHT;
   // If we come here, it is likely caused by the fact that the
   // "VerticalResizeDoubleClick" stored a restore rectangle. In that case
   // we allow all maximize operations (and keep the restore rectangle).
   return FRAME_STATE_NONE;
 }
 
 }  // namespace ash