Suppress leak in MediaGalleriesPreferencesTest

TBR=vandebo@chromium.org
BUG=141322
TEST=none

Review URL: https://chromiumcodereview.appspot.com/10829232

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@150510 0039d316-1c4b-4281-b951-d872f2087c98

tools/heapcheck/suppressions.txt

@@ -1524,4 +1524,11 @@
    fun:policy::AsyncPolicyLoader::ScheduleNextReload
    fun:policy::AsyncPolicyLoader::Init
 }
-
+{
+   bug_141322
+   Heapcheck:Leak
+   ...
+   fun:ExtensionService::ExtensionService
+   fun:extensions::TestExtensionSystem::CreateExtensionService
+   fun:chrome::::MediaGalleriesPreferencesTest::SetUp
+}