clang: Disable new warning -Wbitfield-width on the ToT bots.

build/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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 3090 matching lines @@
       ['<(use_nss_certs)==1 and >(nacl_untrusted_build)==0', {
         'defines': ['USE_NSS_CERTS=1'],
       }],
       ['<(chromeos)==1 and >(nacl_untrusted_build)==0', {
         'defines': ['OS_CHROMEOS=1'],
       }],
       ['enable_wexit_time_destructors==1 and OS!="win"', {
         # TODO: Enable on Windows too, http://crbug.com/404525
         'variables': { 'clang_warning_flags': ['-Wexit-time-destructors']},
       }],
+      ['"<!(python <(DEPTH)/tools/clang/scripts/update.py --print-revision)"!="245965-1"', {
+        # TODO(thakis): Move this to the global clang_warning_flags block once
+        # clang is rolled far enough that the pinned clang understands this flag
+        # TODO(thakis): Consider enabling this?
+        'variables': { 'clang_warning_flags': ['-Wno-bitfield-width']},
+      }],
       ['chromium_code==0', {
         'variables': {
           'clang_warning_flags': [
             # TODO(thakis): Move this suppression into individual third-party
             # libraries as required. http://crbug.com/505316.
             '-Wno-unused-function',
             # Lots of third-party libraries have unused variables. Instead of
             # suppressing them individually, we just blanket suppress them here.
             '-Wno-unused-variable',
           ],
@@ skipping 3179 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }