Revert r162691 "Fix for out-of-sync scale factor issue"

ash/display/multi_display_manager.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/display/multi_display_manager.h"
 
 #include <string>
 #include <vector>
 
 #include "ash/display/display_controller.h"
@@ skipping 299 matching lines @@
 size_t MultiDisplayManager::GetNumDisplays() const {
   return displays_.size();
 }
 
 const gfx::Display& MultiDisplayManager::GetDisplayNearestWindow(
     const Window* window) const {
   if (!window)
     return DisplayController::GetPrimaryDisplay();
   const RootWindow* root = window->GetRootWindow();
   MultiDisplayManager* manager = const_cast<MultiDisplayManager*>(this);
-  return root ?
-      manager->FindDisplayForRootWindow(root) :
-      DisplayController::GetPrimaryDisplay();
+  return root ? manager->FindDisplayForRootWindow(root) : GetInvalidDisplay();
 }
 
 const gfx::Display& MultiDisplayManager::GetDisplayNearestPoint(
     const gfx::Point& point) const {
   // Fallback to the primary display if there is no root display containing
   // the |point|.
   const gfx::Display& display = FindDisplayContainingPoint(point);
   return display.is_valid() ? display : DisplayController::GetPrimaryDisplay();
 }
 
@@ skipping 150 matching lines @@
   DisplayList::iterator iter_to_update = to_update->begin();
   DisplayList::const_iterator iter = displays_.begin();
   for (; iter != displays_.end() && iter_to_update != to_update->end();
        ++iter, ++iter_to_update) {
     (*iter_to_update).set_id((*iter).id());
   }
 }
 
 }  // namespace internal
 }  // namespace ash