Initial implementation of Google Now Notifications integration.

BUG=164227

Review URL: https://chromiumcodereview.appspot.com/11967029

git-svn-id: http://src.chromium.org/svn/trunk/src/build@179497 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -1406,6 +1406,9 @@
       ['enable_settings_app==1', {
         'grit_defines': ['-D', 'enable_settings_app'],
       }],
+      ['enable_google_now==1', {
+        'grit_defines': ['-D', 'enable_google_now'],
+      }],
       ['clang_use_chrome_plugins==1 and OS!="win"', {
         'clang_chrome_plugins_flags': [
           '<!@(<(DEPTH)/tools/clang/scripts/plugin_flags.sh)'