Build aura_shell_unittests on Mac try bot target
Build aura_shell_unittests on Mac try bot target

Enables building of target 'aura_shell_unittest' when building the
'aura_builder' target.  The 'aura_builder' target is used by the try
bots.

BUG=None
TEST=Compiles on Mac try bot
R=oshima@chromium.org

Review URL: https://chromiumcodereview.appspot.com/9317097

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@120453 0039d316-1c4b-4281-b951-d872f2087c98

adobe/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,yitian134/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,ropik/chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,ropik/chromium,yitian134/chromium,yitian134/chromium,gavinp/chromium,adobe/chromium,ropik/chromium,ropik/chromium,ropik/chromium,ropik/chromium,yitian134/chromium,gavinp/chromium,gavinp/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,yitian134/chromium,adobe/chromium