Fix dependency tree when using the system ICU.

ui/ui.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,
   },
   'includes': [
     'shell_dialogs.gypi',
@@ skipping 852 matching lines @@
         ['OS=="linux"', {
           'libraries': [
             '-ldl',
           ],
         }],
         ['inside_chromium_build==0', {
           'dependencies': [
             '<(DEPTH)/webkit/support/setup_third_party.gyp:third_party_headers',
           ],
         }],
+        ['use_system_icu==1', {
+          # When using the system icu, the icu targets generate shim headers
+          # which are included by public headers in the ui target, so we need
+          # ui to be a hard dependency for all its users.
+          'hard_dependency': 1,
+        }],
       ],
     },
   ],
   'conditions': [
     ['inside_chromium_build == 1', {
       'includes': [
         'ui_unittests.gypi',
       ]},
     ],
     ['OS=="android"' , {
@@ skipping 102 matching lines @@
               'xcode_settings': {
                 'GCC_SYMBOLS_PRIVATE_EXTERN': 'NO',
               },
             }],
           ],
         },
       ],
     }],
   ],
 }