Don't process messages sent to dead routing ids.

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 846b49e22d935797bada89aaf0d8ec75d9599477..70bfef190d648d31f3b894bbbd88a055f744f25e 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -444,6 +444,10 @@ bool RenderWidgetHostImpl::IsLoading() const {
 }
 
 bool RenderWidgetHostImpl::OnMessageReceived(const IPC::Message &msg) {
+  // Only process messages if the RenderWidget is alive.
+  if (!renderer_initialized())
+    return false;
+
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(RenderWidgetHostImpl, msg)
     IPC_MESSAGE_HANDLER(FrameHostMsg_RenderProcessGone, OnRenderProcessGone)