Enable the use of system python in testing.

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 215 matching lines @@
       # On Linux, we build with sse2 for Chromium builds.
       'disable_sse2%': 0,
 
       # Use libjpeg-turbo as the JPEG codec used by Chromium.
       'use_libjpeg_turbo%': 1,
 
       # Use system libjpeg. Note that the system's libjepg will be used even if
       # use_libjpeg_turbo is set.
       'use_system_libjpeg%': 0,
 
+      # Use system python instead of the one in third_party.
+      'use_system_python_in_tests%': 0,
+
       # By default, component is set to static_library and it can be overriden
       # by the GYP command line or by ~/.gyp/include.gypi.
       'component%': 'static_library',
 
       # Set to select the Title Case versions of strings in GRD files.
       'use_titlecase_in_grd_files%': 0,
 
       # Use translations provided by volunteers at launchpad.net.  This
       # currently only works on Linux.
       'use_third_party_translations%': 0,
@@ skipping 553 matching lines @@
     'enable_printing%': '<(enable_printing)',
     'enable_google_now%': '<(enable_google_now)',
     'enable_language_detection%': '<(enable_language_detection)',
     'enable_captive_portal_detection%': '<(enable_captive_portal_detection)',
     'disable_ftp_support%': '<(disable_ftp_support)',
     'enable_task_manager%': '<(enable_task_manager)',
     'sas_dll_path%': '<(sas_dll_path)',
     'wix_path%': '<(wix_path)',
     'use_libjpeg_turbo%': '<(use_libjpeg_turbo)',
     'use_system_libjpeg%': '<(use_system_libjpeg)',
+    'use_system_python_in_tests%': '<(use_system_python_in_tests)',
     'android_webview_build%': '<(android_webview_build)',
     'gyp_managed_install%': 0,
     'google_tv%': '<(google_tv)',
     'enable_app_list%': '<(enable_app_list)',
     'use_default_render_theme%': '<(use_default_render_theme)',
     'enable_settings_app%': '<(enable_settings_app)',
     'google_api_key%': '<(google_api_key)',
     'google_default_client_id%': '<(google_default_client_id)',
     'google_default_client_secret%': '<(google_default_client_secret)',
     'enable_managed_users%': '<(enable_managed_users)',
@@ skipping 1312 matching lines @@
               'VCLinkerTool': {
                 # Make the pdb name sane. Otherwise foo.exe and foo.dll both
                 # have foo.pdb. The ninja generator already defaults to this and
                 # can't handle the $(TargetPath) macro.
                 'ProgramDatabaseFile': '$(TargetPath).pdb',
               }
             },
           }],
         ],  # win_z7!=0
       }],  # OS==win
+      ['use_system_python_in_tests==1', {
+        'defines': [
+          'USE_SYSTEM_PYTHON_IN_TESTS=1',
+        ],
+      }],
       ['enable_task_manager==1', {
         'defines': [
           'ENABLE_TASK_MANAGER=1',
         ],
       }],
       ['enable_extensions==1', {
         'defines': [
           'ENABLE_EXTENSIONS=1',
         ],
       }],
@@ skipping 2362 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',
   },
 }