Remove remote tree host and some related input and metro_driver code

ui/aura/aura.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 70 matching lines @@
         'client/window_tree_client.h',
         'env.cc',
         'env.h',
         'env_observer.h',
         'input_state_lookup.cc',
         'input_state_lookup.h',
         'input_state_lookup_win.cc',
         'input_state_lookup_win.h',
         'layout_manager.cc',
         'layout_manager.h',
-        'remote_window_tree_host_win.cc',
-        'remote_window_tree_host_win.h',
         'scoped_window_targeter.cc',
         'scoped_window_targeter.h',
         'window.cc',
         'window.h',
         'window_delegate.h',
         'window_event_dispatcher.cc',
         'window_event_dispatcher.h',
         'window_observer.cc',
         'window_observer.h',
         'window_targeter.cc',
@@ skipping 240 matching lines @@
               'dependencies': [
                 '../../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }