Add the page url to plugin crashes to aid debugging.

chrome/plugin/webplugin_delegate_stub.h

Index: chrome/plugin/webplugin_delegate_stub.h
===================================================================
--- chrome/plugin/webplugin_delegate_stub.h	(revision 20181)
+++ chrome/plugin/webplugin_delegate_stub.h	(working copy)
@@ -13,9 +13,9 @@
 #include "base/task.h"
 #include "chrome/common/ipc_channel.h"
 #include "chrome/common/transport_dib.h"
+#include "googleurl/src/gurl.h"
 #include "third_party/npapi/bindings/npapi.h"
 
-class GURL;
 class PluginChannel;
 class WebPluginProxy;
 class WebPluginDelegate;
@@ -105,6 +105,9 @@
   WebPluginDelegate* delegate_;
   WebPluginProxy* webplugin_;
 
+  // The url of the main frame hosting the plugin.
+  GURL page_url_;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(WebPluginDelegateStub);
 };