Moves common view_manager related aura files to mojo/aura

mojo/mojo.gyp

 # Copyright 2013 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.
 
 {
   'target_defaults': {
     'conditions': [
       ['mojo_shell_debug_url != ""', {
         'defines': [
           'MOJO_SHELL_DEBUG=1',
@@ skipping 879 matching lines @@
             '../ui/events/events.gyp:events',
             '../ui/events/events.gyp:events_base',
             '../ui/compositor/compositor.gyp:compositor',
             '../ui/gl/gl.gyp:gl',
             '../webkit/common/gpu/webkit_gpu.gyp:webkit_gpu',
             'mojo_cc_support',
             'mojo_gles2',
             'mojo_native_viewport_bindings',
           ],
           'sources': [
+            'aura/context_factory_mojo.cc',
+            'aura/context_factory_mojo.h',
             'aura/screen_mojo.cc',
             'aura/screen_mojo.h',
+            'aura/window_tree_host_mojo.cc',
+            'aura/window_tree_host_mojo.h',
+            'aura/window_tree_host_mojo_delegate.h',
           ],
         },
       ],
     }],
   ],
 }