Prevented connecting drag drop events to a SwappedOut RenderViewHost in WebContentsViewGtk

content/port/browser/web_contents_view_port.h

Index: content/port/browser/web_contents_view_port.h
diff --git a/content/port/browser/web_contents_view_port.h b/content/port/browser/web_contents_view_port.h
index 631fe5767119dad64ae40b5f3a2e907057072e8a..9d77b2b865b97c4eb4365cdb175495762a1f1bbd 100644
--- a/content/port/browser/web_contents_view_port.h
+++ b/content/port/browser/web_contents_view_port.h
@@ -42,8 +42,9 @@ class CONTENT_EXPORT WebContentsViewPort : public WebContentsView {
   virtual void RenderViewCreated(RenderViewHost* host) = 0;
 
   // Invoked when the WebContents is notified that the RenderView has been
-  // swapped in.
-  virtual void RenderViewSwappedIn(RenderViewHost* host) = 0;
+  // swapped in. |old_host| may be null.

[Charlie Reis, 2013/02/27 01:42:35]

When will it be null, and what does that mean?

[mthiesse, 2013/02/27 14:57:13]

Well right now, never. I just didn't want to force the RenderViewSwappedIn call
to include an old host, as I'm not sure that is necessarily going to be true
going forward.

[Charlie Reis, 2013/02/27 20:01:44]

Let's avoid that case if we decide to keep old_host in the API.  It's much
better to provide clean values than make all callers check, so this should never
be null.

+  virtual void RenderViewSwappedIn(RenderViewHost* new_host,
+                                   RenderViewHost* old_host) = 0;
 
 #if defined(OS_MACOSX)
   // If we close the tab while a UI control is in an event-tracking