RenderViewHostDelegate: add missing 'virtual'

content/browser/renderer_host/render_view_host_delegate.h

Index: content/browser/renderer_host/render_view_host_delegate.h
diff --git a/content/browser/renderer_host/render_view_host_delegate.h b/content/browser/renderer_host/render_view_host_delegate.h
index 8239ba31a0c7408679fdf428910a95392662a756..c3c74470a68c08ebb751d89154c4cddb35501af9 100644
--- a/content/browser/renderer_host/render_view_host_delegate.h
+++ b/content/browser/renderer_host/render_view_host_delegate.h
@@ -327,7 +327,7 @@ class RenderViewHostDelegate : public IPC::Channel::Listener {
                                 uint64 upload_position, uint64 upload_size) {}
 
   // Notification that a worker process has crashed.
-  void WorkerCrashed() {}
+  virtual void WorkerCrashed() {}
 
   // The page wants the hosting window to activate/deactivate itself (it
   // called the JavaScript window.focus()/blur() method).