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

mojo/runner/about_fetcher_unittest.cc

Index: mojo/runner/about_fetcher_unittest.cc
diff --git a/mojo/runner/about_fetcher_unittest.cc b/mojo/runner/about_fetcher_unittest.cc
index 08470b5340724109ccb9782abd37dfb75f64bd15..0dfd7a18d322b046d78f9c29d3c920ea79e7fc6c 100644
--- a/mojo/runner/about_fetcher_unittest.cc
+++ b/mojo/runner/about_fetcher_unittest.cc
@@ -135,7 +135,7 @@ class AboutFetcherTest : public testing::Test {
     application_manager_->ConnectToApplication(
         nullptr, request.Pass(), std::string(), GURL(),
         service_provider_request.Pass(), nullptr, shell::CapabilityFilter(),
-        base::Closure());
+        base::Closure(), shell::EmptyConnectCallback());
 
     run_loop.Run();
   }