Move ContentWindow from BrowserPlugin To GuestView

extensions/common/extension_messages.h

Index: extensions/common/extension_messages.h
diff --git a/extensions/common/extension_messages.h b/extensions/common/extension_messages.h
index 8b090ca9ae637b250244177aeef765088b6a932c..d2aadea6b5859d8bf80f4f5d9e9eda185d87a129 100644
--- a/extensions/common/extension_messages.h
+++ b/extensions/common/extension_messages.h
@@ -516,6 +516,12 @@ IPC_MESSAGE_CONTROL1(ExtensionMsg_TransferBlobs,
 IPC_MESSAGE_CONTROL1(ExtensionMsg_CreateMimeHandlerViewGuestACK,
                      int /* element_instance_id */)
 
+// Once a RenderView proxy has been created for the guest in the embedder render
+// process, this IPC informs the embedder of the proxy's routing ID.
+IPC_MESSAGE_ROUTED2(ExtensionMsg_GuestAttached,
+                    int /* element_instance_id */,
+                    int /* source_routing_id */)
+
 // Messages sent from the renderer to the browser.
 
 // A renderer sends this message when an extension process starts an API