Update view_manager and window_manager to make use of content handling.

mojo/mojo_examples.gypi

 # 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.
 
 {
   'targets': [
     {
       # GN version: //mojo/examples/echo:client
       'target_name': 'mojo_echo_client',
       'type': 'loadable_module',
@@ skipping 225 matching lines @@
     },
     {
       'target_name': 'mojo_png_viewer',
       'type': 'loadable_module',
       'dependencies': [
         '../skia/skia.gyp:skia',
         '../ui/gfx/gfx.gyp:gfx',
         'mojo_base.gyp:mojo_application_chromium',
         'mojo_base.gyp:mojo_cpp_bindings',
         'mojo_base.gyp:mojo_utility',
+        'mojo_content_handler_bindings',
         'mojo_media_viewer_bindings',
-        'mojo_navigation_bindings',
         'mojo_network_bindings',
         'mojo_launcher_bindings',
         'mojo_view_manager_lib',
         '<(mojo_system_for_loadable_module)',
       ],
       'sources': [
         'examples/png_viewer/png_viewer.cc',
       ],
     },
     {
@@ skipping 605 matching lines @@
           ],
           'sources': [
             'examples/dbus_echo/dbus_echo_service.cc',
           ],
         },
       ],
 
     }],
   ],
 }