Add keyboard handler for mime-handler-view.

extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.h

Index: extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.h
diff --git a/extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.h b/extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.h
index f3baaff62555151e281344a77cf50a5e592c15bc..3eff421b3c74155ccc68581912d400742180cb17 100644
--- a/extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.h
+++ b/extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.h
@@ -26,6 +26,11 @@ class MimeHandlerViewGuest : public GuestView<MimeHandlerViewGuest> {
       const WebContentsCreatedCallback& callback) OVERRIDE;
   virtual void DidAttachToEmbedder() OVERRIDE;
 
+  // WebContentsDelegate implementation.
+  virtual void HandleKeyboardEvent(
+      content::WebContents* source,
+      const content::NativeWebKeyboardEvent& event) OVERRIDE;
+
  private:
   MimeHandlerViewGuest(content::BrowserContext* browser_context,
                        int guest_instance_id);