Teach sky_viewer about the new main.dart hotness

sky/engine/core/script/dart_controller.cc

Index: sky/engine/core/script/dart_controller.cc
diff --git a/sky/engine/core/script/dart_controller.cc b/sky/engine/core/script/dart_controller.cc
index 22fe4d38f73edbcdbfb7894bd28acb4e4ee61a31..083e19099bb397b77886de48009ddf4183eac2cb 100644
--- a/sky/engine/core/script/dart_controller.cc
+++ b/sky/engine/core/script/dart_controller.cc
@@ -120,10 +120,10 @@ void DartController::DidLoadMainLibrary(KURL url) {
   DartInvokeAppField(library, ToDart("main"), 0, nullptr);
 }
 
-void DartController::LoadMainLibrary(const KURL& url) {
+void DartController::LoadMainLibrary(const KURL& url, mojo::URLResponsePtr response) {
   DartLoader& loader = dart_state()->loader();
   DartDependencyCatcher dependency_catcher(loader);
-  loader.LoadLibrary(url);
+  loader.LoadLibrary(url, response.Pass());
   loader.WaitForDependencies(dependency_catcher.dependencies(),
                              base::Bind(&DartController::DidLoadMainLibrary, weak_factory_.GetWeakPtr(), url));
 }