Exclude notification strings for builds that dont use it.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 07a420b950fa4df2fe0cf7915b5ae39da6894b61..abff975f1ae6748a5e557d8b4c0657840a31dffa 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -616,6 +616,9 @@
           'native_memory_pressure_signals%': 1,
           'enable_printing%': 2,
           'enable_task_manager%':0,
+           # Set to 1 once we have a notification system for Android.
+           # http://crbug.com/115320
+          'notifications%': 0,
         }],
 
         # Android OS includes support for proprietary codecs regardless of
@@ -1463,10 +1466,6 @@
         # Sessions are store separately in the Java side.
         'enable_session_service%': 0,
 
-        # Set to 1 once we have a notification system for Android.
-        # http://crbug.com/115320
-        'notifications%': 0,
-
         'p2p_apis%' : 0,
 
         'gtest_target_type%': 'shared_library',
@@ -1771,6 +1770,9 @@
       ['enable_task_manager==1', {
         'grit_defines': ['-D', 'enable_task_manager'],
       }],
+      ['notifications==1', {
+        'grit_defines': ['-D', 'enable_notifications'],
+      }],
       ['clang_use_chrome_plugins==1 and OS!="win"', {
         'clang_chrome_plugins_flags': [
           '<!@(<(DEPTH)/tools/clang/scripts/plugin_flags.sh)'