Update view_manager and window_manager to make use of content handling.

mojo/public/cpp/application/application_impl.h

Index: mojo/public/cpp/application/application_impl.h
diff --git a/mojo/public/cpp/application/application_impl.h b/mojo/public/cpp/application/application_impl.h
index 809c3725bb7ccc8d972180129b99ca270dd22bce..8d6ebd77c0ea3dbde551d1363d349bab8144e50b 100644
--- a/mojo/public/cpp/application/application_impl.h
+++ b/mojo/public/cpp/application/application_impl.h
@@ -58,6 +58,8 @@ class ApplicationImpl : public InterfaceImpl<Application> {
                   MojoHandle shell_handle);
   virtual ~ApplicationImpl();
 
+  Shell* shell() const { return shell_.get(); }
+
   // Establishes a new connection to an application. Caller does not own.
   ApplicationConnection* ConnectToApplication(const String& application_url);