ui: Have shell_dialogs into its own gyp file under its shell_dialogs/ directory.

content/content_common.gypi

 # 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.
 
 {
   'dependencies': [
     '../base/base.gyp:base',
     '../components/tracing.gyp:tracing',
     '../net/net.gyp:net',
     '../skia/skia.gyp:skia',
     '../third_party/icu/icu.gyp:icuuc',
     '../ui/gfx/gfx.gyp:gfx',
-    '../ui/ui.gyp:shell_dialogs',
+    '../ui/shell_dialogs/shell_dialogs.gyp:shell_dialogs',
     '../ui/ui.gyp:ui',
     '../url/url.gyp:url_lib',
     '../webkit/common/user_agent/webkit_user_agent.gyp:user_agent',
   ],
   'include_dirs': [
     '..',
   ],
   'export_dependent_settings': [
     '../base/base.gyp:base',
   ],
@@ skipping 562 matching lines @@
         '..\\third_party\\directxsdk\\files\\Redist\\<(input)',
         '<(output)',
         '<(PRODUCT_DIR)',
         ],
         'msvs_cygwin_shell': 1,
       },
      ]
     }],
   ],
 }