Remove CHROME_V8 #define and related javascript_engine gyp variable.

chrome/chrome_browser.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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
       'dependencies': [
@@ skipping 3819 matching lines @@
         # These files are generated by GRIT.
         '<(grit_out_dir)/grit/component_extension_resources_map.cc',
         '<(grit_out_dir)/grit/devtools_frontend_resources_map.cc',
         '<(grit_out_dir)/grit/devtools_resources_map.cc',
         '<(grit_out_dir)/grit/shared_resources_map.cc',
         '<(grit_out_dir)/grit/theme_resources_map.cc',
         '<(grit_out_dir)/grit/theme_resources_large_map.cc',
         '<(grit_out_dir)/grit/theme_resources_standard_map.cc',
       ],
       'conditions': [
-        ['javascript_engine=="v8"', {
-          'defines': [
-            'CHROME_V8',
-          ],
-        }],
         ['debug_devtools==1', {
           'defines': [
             'DEBUG_DEVTOOLS=1',
           ],
         }],
         ['configuration_policy==0', {
           'sources!': [
             'browser/ui/webui/options/options_managed_banner_handler.cc',
           ],
           'sources/': [
@@ skipping 1189 matching lines @@
               # weak imports in dependents, who still must #include
               # closure_blocks_leopard_compat.h to get weak imports.
               'type': 'none',
             }],
           ],
         },
       ],
     }],
   ],
 }