Get rid of app/ directory as it's no longer used (finally).

chrome/chrome.gyp

 # Copyright (c) 2011 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,
 
     'variables': {
       'version_py_path': 'tools/build/version.py',
       'version_path': 'VERSION',
@@ skipping 1337 matching lines @@
       { 'targets': [
         {
           # TODO(sgk):  remove this when we change the buildbots to
           # use the generated build\all.sln file to build the world.
           'target_name': 'pull_in_all',
           'type': 'none',
           'dependencies': [
             'installer/mini_installer.gyp:*',
             'installer/installer_tools.gyp:*',
             'installer/upgrade_test.gyp:*',
-            '../app/app.gyp:*',
             '../base/base.gyp:*',
             '../chrome_frame/chrome_frame.gyp:*',
             '../content/content.gyp:*',
             '../ipc/ipc.gyp:*',
             '../media/media.gyp:*',
             '../net/net.gyp:*',
             '../ppapi/ppapi.gyp:*',
             '../ppapi/ppapi_internal.gyp:*',
             '../printing/printing.gyp:*',
             '../sdch/sdch.gyp:*',
@@ skipping 304 matching lines @@
             'destination': '<(PRODUCT_DIR)',
             'files': [
               '<(INTERMEDIATE_DIR)/repack/chrome.pak'
             ],
           },
         ],
       }],  # targets
     }],  # os_posix == 1 and OS != "mac"
   ],  # 'conditions'
 }