GuestView: Fix message routing across embedder navigations

content/browser/browser_plugin/browser_plugin_embedder.cc

Index: content/browser/browser_plugin/browser_plugin_embedder.cc
diff --git a/content/browser/browser_plugin/browser_plugin_embedder.cc b/content/browser/browser_plugin/browser_plugin_embedder.cc
index 5313268a62405ca70663c29dd504a43baa501847..132bbd27f6a47032fb47a713c8ca921573735984 100644
--- a/content/browser/browser_plugin/browser_plugin_embedder.cc
+++ b/content/browser/browser_plugin/browser_plugin_embedder.cc
@@ -98,8 +98,15 @@ void BrowserPluginEmbedder::DidSendScreenRects() {
 }
 
 bool BrowserPluginEmbedder::OnMessageReceived(const IPC::Message& message) {
+  return OnMessageReceived(message, nullptr);
+}
+
+bool BrowserPluginEmbedder::OnMessageReceived(
+    const IPC::Message& message,
+    RenderFrameHost* render_frame_host) {
   bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(BrowserPluginEmbedder, message)
+  IPC_BEGIN_MESSAGE_MAP_WITH_PARAM(BrowserPluginEmbedder, message,
+                                   render_frame_host)
     IPC_MESSAGE_HANDLER(BrowserPluginHostMsg_Attach, OnAttach)
     IPC_MESSAGE_HANDLER_GENERIC(DragHostMsg_UpdateDragCursor,
                                 OnUpdateDragCursor(&handled));
@@ -135,11 +142,17 @@ void BrowserPluginEmbedder::OnUpdateDragCursor(bool* handled) {
 }
 
 void BrowserPluginEmbedder::OnAttach(
+    RenderFrameHost* render_frame_host,
     int browser_plugin_instance_id,
     const BrowserPluginHostMsg_Attach_Params& params) {
+  int owner_process_id = render_frame_host ?

[Charlie Reis, 2015/02/13 21:21:56]

I don't think we should support the case that this message arrives without going
through RFH, if we're depending on that to get the process ID correct.  We
should probably return early if render_frame_host doesn't exist.

And actually, it looks like this won't work yet.  BrowserPluginHostMsg_Attach is
sent using a render_view_routing_id_ (in browser_plugin.cc), so it never goes
through RFH.

[Fady Samuel, 2015/02/13 22:31:25]

Using the GetWebContents()->GetRenderProcessHost()->GetID() for now and added
TODO.

+      render_frame_host->GetProcess()->GetID() :
+      GetWebContents()->GetRenderProcessHost()->GetID();
+
   WebContents* guest_web_contents =
       GetBrowserPluginGuestManager()->GetGuestByInstanceID(
-          GetWebContents(), browser_plugin_instance_id);
+          owner_process_id,
+          browser_plugin_instance_id);
   if (!guest_web_contents)
     return;
   BrowserPluginGuest* guest = static_cast<WebContentsImpl*>(guest_web_contents)