Move build_dir_prefix up a level of nesting so we don't create

build/common.gypi

 # Copyright (c) 2011 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 864 matching lines @@
       # std::partial_sort in Debug build which make them O(N^2)
       # instead of O(N*logN). This is particularly slow under memory
       # tools like ThreadSanitizer so we want it to be disablable.
       # See http://msdn.microsoft.com/en-us/library/aa985982(v=VS.80).aspx
       'win_debug_disable_iterator_debugging%': '0',
 
       'release_extra_cflags%': '',
       'debug_extra_cflags%': '',
       'release_valgrind_build%': 0,
 
+      # Only used by Windows build for now.  Can be used to build into a
+      # differet output directory, e.g., a build_dir_prefix of VS2010_ would
+      # output files in src/build/VS2010_{Debug,Release}.
+      'build_dir_prefix%': '',
+
       'conditions': [
         ['OS=="win" and component=="shared_library"', {
           # See http://msdn.microsoft.com/en-us/library/aa652367.aspx
           'win_release_RuntimeLibrary%': '2', # 2 = /MT (nondebug DLL)
           'win_debug_RuntimeLibrary%': '3',   # 3 = /MTd (debug DLL)
         }, {
           # See http://msdn.microsoft.com/en-us/library/aa652367.aspx
           'win_release_RuntimeLibrary%': '0', # 0 = /MT (nondebug static)
           'win_debug_RuntimeLibrary%': '1',   # 1 = /MTd (debug static)
         }],
@@ skipping 330 matching lines @@
             'sources/': [ ['exclude', '_views\\.(h|cc)$'] ]
           }],
           ['use_aura==0', {
             'sources/': [ ['exclude', '_aura\\.(h|cc)$'] ]
           }],
         ],
       }],
     ],  # target_conditions for 'target_defaults'
     'default_configuration': 'Debug',
     'configurations': {
-      'variables' : {
-        # Only used by Windows build for now.  Can be used to build into a
-        # differet output directory, e.g., a build_dir_prefix of VS2010_ would
-        # output files in src/build/VS2010_{Debug,Release}.
-        'build_dir_prefix%': '',
-      },
       # VCLinkerTool LinkIncremental values below:
       #   0 == default
       #   1 == /INCREMENTAL:NO
       #   2 == /INCREMENTAL
       # Debug links incremental, Release does not.
       #
       # Abstract base configurations to cover common attributes.
       #
       'Common_Base': {
         'abstract': 1,
@@ skipping 1241 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',
   },
 }