Add "panel_fitting" GPU feature type and use it for mirror mode.

ash/ash_switches.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/ash_switches.h"
 
 namespace ash {
 namespace switches {
 
 // Constrains the pointer movement within a root window on desktop.
 const char kAshConstrainPointerToRoot[] = "ash-constrain-pointer-to-root";
 
 // Enable keyboard shortcuts useful for debugging.
 const char kAshDebugShortcuts[] = "ash-debug-shortcuts";
 
 // Disables Workspace2.
 const char kAshDisableWorkspace2[] = "ash-disable-workspace2";
 
+// Disables panel fitting (used for mirror mode).
+const char kAshDisablePanelFitting[] = "ash-disable-panel-fitting";
+
 // Enable advanced gestures (e.g. for window management).
 const char kAshEnableAdvancedGestures[] = "ash-enable-advanced-gestures";
 
 // Enables the Oak tree viewer.
 const char kAshEnableOak[] = "ash-enable-oak";
 
 // Disable using Ash notifications.
 const char kAshNotifyDisabled[] = "ash-notify-disabled";
 
 // Specifies the layout mode and offsets for the secondary display for
@@ skipping 15 matching lines @@
 // Standard hardware reports releases immediately after presses.  If set, we
 // lock the screen or shutdown the system immediately in response to a press
 // instead of displaying an interactive animation.
 const char kAuraLegacyPowerButton[] = "aura-legacy-power-button";
 
 // Avoid drawing drop shadows under windows.
 const char kAuraNoShadows[] = "aura-no-shadows";
 
 }  // namespace switches
 }  // namespace ash