webkit: expose webkit branch and revision number in about pages

webkit/glue/webkit_glue.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.
 
 {
   'variables': {
     'conditions': [
       ['inside_chromium_build==0', {
         'webkit_src_dir': '../../../../..',
       },{
@@ skipping 102 matching lines @@
       'type': '<(library)',
       'msvs_guid': 'DB162DE1-7D56-4C4A-8A9F-80D396CD7AA8',
       'dependencies': [
         '<(DEPTH)/app/app.gyp:app_base',
         '<(DEPTH)/base/base.gyp:base_i18n',
       ],
       'actions': [
         {
           'action_name': 'webkit_version',
           'inputs': [
-            '../build/webkit_version.py',
-            '<(webkit_src_dir)/Source/WebCore/Configurations/Version.xcconfig',
+            '<(script)',
+            '<(webkit_src_dir)<(version_file)',
+            '../../build/util/lastchange.py',  # Used by the script.
           ],
           'outputs': [
             '<(INTERMEDIATE_DIR)/webkit_version.h',
           ],
-          'action': ['python', '<@(_inputs)', '<(INTERMEDIATE_DIR)'],
+          'action': ['python', '<(script)', '<(webkit_src_dir)',
+                     '<(version_file)', '<(INTERMEDIATE_DIR)'],
+          'variables': {
+            'script': '../build/webkit_version.py',
+            # version_file is a relative path from |webkit_src_dir| to
+            # the version file.  But gyp will eat the variable unless
+            # it looks like an absolute path, so write it like one and
+            # then use it carefully above.
+            'version_file': '/Source/WebCore/Configurations/Version.xcconfig',
+          },
         },
       ],
       'include_dirs': [
         '<(INTERMEDIATE_DIR)',
       ],
       'sources': [
         'user_agent.cc',
         'user_agent.h',
       ],
       # Dependents may rely on files generated by this target or one of its
@@ skipping 384 matching lines @@
         }],
         ['inside_chromium_build==0', {
           'dependencies': [
             '<(DEPTH)/webkit/support/setup_third_party.gyp:third_party_headers',
           ],
         }],
       ],
     },
   ],
 }