linux_aura: Compile ash into chrome.

ash/host/ash_window_tree_host_x11.h

 // Copyright 2014 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.
 
 #ifndef ASH_HOST_ASH_WINDOW_TREE_HOST_X11_H_
 #define ASH_HOST_ASH_WINDOW_TREE_HOST_X11_H_
 
 #include "ash/ash_export.h"
 #include "ash/host/ash_window_tree_host.h"
 #include "ash/host/transformer_helper.h"
@@ skipping 35 matching lines @@
 
   // EnvObserver overrides.
   virtual void OnWindowInitialized(aura::Window* window) OVERRIDE;
   virtual void OnHostInitialized(aura::WindowTreeHost* host) OVERRIDE;
 
   class TouchEventCalibrate;
 
   // Update is_internal_display_ based on the current state.
   void UpdateIsInternalDisplay();
 
+#if defined(OS_CHROMEOS)
   // Set the CrOS touchpad "tap paused" property. It is used to temporarily
   // turn off the Tap-to-click feature when the mouse pointer is invisible.
   void SetCrOSTapPaused(bool state);
+#endif
 
   // True if the root host resides on the internal display
   bool is_internal_display_;
 
   scoped_ptr<XID[]> pointer_barriers_;
 
   scoped_ptr<TouchEventCalibrate> touch_calibrate_;
 
   TransformerHelper transformer_helper_;
 
   DISALLOW_COPY_AND_ASSIGN(AshWindowTreeHostX11);
 };
 
 }  // namespace ash
 
 #endif  // ASH_HOST_ASH_WINDOW_TREE_HOST_X11_H_