Support Express for 2013 automatic toolchain

build/gyp_chromium

Index: build/gyp_chromium
diff --git a/build/gyp_chromium b/build/gyp_chromium
index d05204b77f2b769af4a1436a45870dcb6fbb5ba9..0260c2e085c1476bbce6bab61a134ae6500d297e 100755
--- a/build/gyp_chromium
+++ b/build/gyp_chromium
@@ -397,23 +397,29 @@ if __name__ == '__main__':
     depot_tools_path = find_depot_tools.add_depot_tools_to_path()
     toolchain = os.path.normpath(os.path.join(
         depot_tools_path, 'win_toolchain', 'vs2013_files'))
-    if os.path.isdir(toolchain):
+    version_file = os.path.join(toolchain, '.version')
+    if os.path.isdir(toolchain) and os.path.isfile(version_file):
       os.environ['GYP_MSVS_OVERRIDE_PATH'] = toolchain
-      os.environ['GYP_MSVS_VERSION'] = '2013'
+      with open(version_file, 'r') as f:
+        version_is_pro = f.read().strip() == 'pro'
+      os.environ['GYP_MSVS_VERSION'] = '2013' if version_is_pro else '2013e'
       # We need to make sure windows_sdk_path is set to the automated
       # toolchain values in GYP_DEFINES, but don't want to override any other
       # values there.
       gyp_defines_dict = gyp.NameValueListToDict(gyp.ShlexEnv('GYP_DEFINES'))
       win8sdk = os.path.join(toolchain, 'win8sdk')
+      wdk = os.path.join(toolchain, 'wdk')
       gyp_defines_dict['windows_sdk_path'] = win8sdk
       os.environ['WINDOWSSDKDIR'] = win8sdk
+      os.environ['WDK_DIR'] = wdk
       os.environ['GYP_DEFINES'] = ' '.join('%s=%s' % (k, pipes.quote(str(v)))
           for k, v in gyp_defines_dict.iteritems())
       # Include the VS runtime in the PATH in case it's not machine-installed.
       runtime_path = ';'.join(os.path.normpath(os.path.join(toolchain, s))
                               for s in ('sys64', 'sys32'))
       os.environ['PATH'] = runtime_path + ';' + os.environ['PATH']
-      print('Using automatic toolchain in %s.' % toolchain)
+      print('Using automatic toolchain in %s (%s edition).' % (
+                toolchain, 'Pro' if version_is_pro else 'Express'))
 
   # If CHROMIUM_GYP_SYNTAX_CHECK is set to 1, it will invoke gyp with --check
   # to enfore syntax checking.