Enable extended desktop by default.

ash/display/display_controller.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/display_controller.h"
 
 #include "ash/ash_switches.h"
 #include "ash/display/multi_display_manager.h"
 #include "ash/root_window_controller.h"
 #include "ash/screen_ash.h"
 #include "ash/shell.h"
 #include "ash/wm/window_util.h"
 #include "base/command_line.h"
 #include "ui/aura/env.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/screen.h"
 
 namespace ash {
 namespace internal {
-namespace {
-// True if the extended desktop mode is enabled.
-bool extended_desktop_enabled = false;
-}  // namespace
 
 DisplayController::DisplayController()
     : secondary_display_layout_(RIGHT) {
   aura::Env::GetInstance()->display_manager()->AddObserver(this);
 }
 
 DisplayController::~DisplayController() {
   aura::Env::GetInstance()->display_manager()->RemoveObserver(this);
   // Delete all root window controllers, which deletes root window
   // from the last so that the primary root window gets deleted last.
@@ skipping 190 matching lines @@
       controller->MoveWindowsTo(Shell::GetPrimaryRootWindow());
       delete controller;
     } else {
       delete root;
     }
   }
 }
 
 // static
 bool DisplayController::IsExtendedDesktopEnabled(){
-  return extended_desktop_enabled ||
+  static bool extended_desktop_disabled =
       CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kAshExtendedDesktop);
-}
-
-// static
-void DisplayController::SetExtendedDesktopEnabled(bool enabled) {
-  extended_desktop_enabled = enabled;
+          switches::kAshExtendedDesktopDisabled);
+  return !extended_desktop_disabled;
 }
 
 aura::RootWindow* DisplayController::AddRootWindowForDisplay(
     const gfx::Display& display) {
   aura::RootWindow* root = aura::Env::GetInstance()->display_manager()->
       CreateRootWindowForDisplay(display);
   root_windows_[display.id()] = root;
   // Confine the cursor within the window if
   // 1) Extended desktop is enabled or
   // 2) the display is primary display and the host window
@@ skipping 34 matching lines @@
       break;
   }
   gfx::Insets insets = secondary_display->GetWorkAreaInsets();
   secondary_display->set_bounds(
       gfx::Rect(new_secondary_origin, secondary_bounds.size()));
   secondary_display->UpdateWorkAreaFromInsets(insets);
 }
 
 }  // namespace internal
 }  // namespace ash