Extract shell methods from ApplicationImpl into a base class, and pass this to Initialize() instead.

components/clipboard/clipboard_application_delegate.h

Index: components/clipboard/clipboard_application_delegate.h
diff --git a/components/clipboard/clipboard_application_delegate.h b/components/clipboard/clipboard_application_delegate.h
index 4cb6d5749920a2a047936f8a99a82fd5c4eb8204..18b8b0476edb92f5f5c3538bb210b6ef8de2f202 100644
--- a/components/clipboard/clipboard_application_delegate.h
+++ b/components/clipboard/clipboard_application_delegate.h
@@ -25,7 +25,8 @@ class ClipboardApplicationDelegate
   ~ClipboardApplicationDelegate() override;
 
   // mojo::ApplicationDelegate implementation.
-  void Initialize(mojo::ApplicationImpl* app) override;
+  void Initialize(mojo::Shell* shell, const std::string& url,
+                  uint32_t id) override;
   bool AcceptConnection(
       mojo::ApplicationConnection* connection) override;