Adds a way to determine id of content handler that created app

mojo/shell/capability_filter_unittest.cc

Index: mojo/shell/capability_filter_unittest.cc
diff --git a/mojo/shell/capability_filter_unittest.cc b/mojo/shell/capability_filter_unittest.cc
index fda2c314d3044660ea7270d9368239f3495c38fc..3449e186cf2638e6b95d13baaee19de416799af1 100644
--- a/mojo/shell/capability_filter_unittest.cc
+++ b/mojo/shell/capability_filter_unittest.cc
@@ -352,7 +352,7 @@ class CapabilityFilterTest : public testing::Test {
     application_manager_->ConnectToApplication(
         nullptr, request.Pass(), std::string(), GURL(), GetProxy(&services),
         exposed_services.Pass(), filter,
-        base::MessageLoop::QuitWhenIdleClosure());
+        base::MessageLoop::QuitWhenIdleClosure(), EmptyConnectCallback());
   }
 
   void InitValidator(const std::set<std::string>& expectations) {