Force inclusion of build/common.gypi for all chromium gyp files.

build/common.gypi

 # Copyright (c) 2009 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.
 {

[Mark Mentovai, 2009/09/15 21:49:57]

Nit: leave a blank line between your comment block and the {.

   'variables': {
     # .gyp files should set chromium_code to 1 if they build Chromium-specific
     # code, as opposed to external code.  This variable is used to control
     # such things as the set of warnings to enable, and whether warnings are
     # treated as errors.
     'chromium_code%': 0,
 
     # Variables expected to be overriden on the GYP command line (-D) or by
     # ~/.gyp/include.gypi.
 
@@ skipping 773 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',
   },
 }