Disable "taking address of packed member" clang warning.

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 2611 matching lines @@
         '-Wno-deprecated-register',
 
         # TODO(hans): Get this cleaned up, http://crbug.com/428099
         '-Wno-inconsistent-missing-override',
 
         # TODO(thakis): Enable this, crbug.com/507717
         '-Wno-shift-negative-value',
 
         # TODO(thakis): https://crbug.com/604888
         '-Wno-undefined-var-template',
+
+        # TODO(eugenis): Clean up, http://crbug.com/619640
+        "-Wno-address-of-packed-member",

[hans, 2016/06/13 18:36:46]

Since this is a new warning flag, the currently used Clang version will error
complaining that it does know the flag.

The flag needs to be added conditionally (also for gn), see e.g.
https://codereview.chromium.org/2040533003

       ],
     },
     'includes': [ 'set_clang_warning_flags.gypi', ],
     'defines': [
       # Don't use deprecated V8 APIs anywhere.
       'V8_DEPRECATION_WARNINGS',
     ],
     'include_dirs': [
       '<(SHARED_INTERMEDIATE_DIR)',
     ],
@@ skipping 3696 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',
   },
 }