Cache ShellImpl by resolved URL, not initial URL

mojo/shell/context.h

Index: mojo/shell/context.h
diff --git a/mojo/shell/context.h b/mojo/shell/context.h
index 5b559101c662bbd2efa8c5061be4d12c57d60f23..33fb26693313d6aafa4a542103c0322444d16b36 100644
--- a/mojo/shell/context.h
+++ b/mojo/shell/context.h
@@ -33,9 +33,6 @@ class Context : ApplicationManager::Delegate {
 
   void Init();
 
-  // ApplicationManager::Delegate override.
-  void OnApplicationError(const GURL& gurl) override;
-
   void Run(const GURL& url);
   ScopedMessagePipeHandle ConnectToServiceByName(
       const GURL& application_url,
@@ -53,6 +50,10 @@ class Context : ApplicationManager::Delegate {
  private:
   class NativeViewportApplicationLoader;
 
+  // ApplicationManager::Delegate override.
+  void OnApplicationError(const GURL& url) override;
+  GURL ResolveURL(const GURL& url) override;
+
   std::set<GURL> app_urls_;
   scoped_ptr<TaskRunners> task_runners_;
   scoped_ptr<ExternalApplicationListener> listener_;