Plumb invalidations from Tango to the extensions code for the Push Messaging API.

BUG=139661,139663

Review URL: https://chromiumcodereview.appspot.com/10826156

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@152877 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extension_system.cc b/chrome/browser/extensions/extension_system.cc
index 086d2ef..8c7c39d0 100644
--- a/chrome/browser/extensions/extension_system.cc
+++ b/chrome/browser/extensions/extension_system.cc
@@ -191,6 +191,11 @@
   }
 }
 
+void ExtensionSystemImpl::Shared::Shutdown() {
+  if (extension_service_.get())
+    extension_service_->Shutdown();
+}
+
 StateStore* ExtensionSystemImpl::Shared::state_store() {
   return state_store_.get();
 }