GYP fix: toolkit_uses_gtk% should be dependent on use_aura%.

This fixes the linux_aura FYI builder. This was broken in r127620.

BUG=none
TEST=none


Review URL: http://codereview.chromium.org/9789002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@127858 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -325,7 +325,7 @@
         }],
 
         # Set toolkit_uses_gtk for the Chromium browser on Linux.
-        ['OS=="linux" and chromeos==0', {
+        ['OS=="linux" and use_aura==0', {
           'toolkit_uses_gtk%': 1,
         }, {
           'toolkit_uses_gtk%': 0,