Add IPC to notify BrowserPlugin when RenderProcess is ready.

content/common/browser_plugin/browser_plugin_messages.h

Index: content/common/browser_plugin/browser_plugin_messages.h
diff --git a/content/common/browser_plugin/browser_plugin_messages.h b/content/common/browser_plugin/browser_plugin_messages.h
index ada018389902df91652d2a852c7afd1ecd62139a..81a54d595ed4b05617ef480abb623d6d55c2810f 100644
--- a/content/common/browser_plugin/browser_plugin_messages.h
+++ b/content/common/browser_plugin/browser_plugin_messages.h
@@ -162,6 +162,9 @@ IPC_MESSAGE_ROUTED3(BrowserPluginHostMsg_RequireSequence,
 IPC_MESSAGE_CONTROL1(BrowserPluginMsg_GuestGone,
                      int /* browser_plugin_instance_id */)
 
+IPC_MESSAGE_CONTROL1(BrowserPluginMsg_GuestReady,
+                     int /* browser_plugin_instance_id */)
+
 // When the user tabs to the end of the tab stops of a guest, the browser
 // process informs the embedder to tab out of the browser plugin.
 IPC_MESSAGE_CONTROL2(BrowserPluginMsg_AdvanceFocus,