Don't process messages sent to dead routing ids.

content/test/web_contents_observer_sanity_checker.cc

Index: content/test/web_contents_observer_sanity_checker.cc
diff --git a/content/test/web_contents_observer_sanity_checker.cc b/content/test/web_contents_observer_sanity_checker.cc
index 79bf062e8fe8fbaf0f26c156b7ca1591d98418aa..c6f19bcf73ae700a97e956aeb793261a4aa0dac7 100644
--- a/content/test/web_contents_observer_sanity_checker.cc
+++ b/content/test/web_contents_observer_sanity_checker.cc
@@ -317,10 +317,7 @@ bool WebContentsObserverSanityChecker::OnMessageReceived(
   // should not be leaking outside of RenderFrameHost.
   CHECK(message.type() != FrameHostMsg_RenderProcessGone::ID);
 
-#if !defined(OS_MACOSX)
-// TODO(avi): Disabled because of http://crbug.com/445054

[nasko, 2015/12/18 15:10:51]

Yay!

   AssertRenderFrameExists(render_frame_host);
-#endif
   return false;
 }
 
@@ -343,6 +340,8 @@ WebContentsObserverSanityChecker::~WebContentsObserverSanityChecker() {
 void WebContentsObserverSanityChecker::AssertRenderFrameExists(
     RenderFrameHost* render_frame_host) {
   CHECK(!web_contents_destroyed_);
+  CHECK(render_frame_host->IsRenderFrameLive());
+
   GlobalRoutingID routing_pair = GetRoutingPair(render_frame_host);
 
   bool render_frame_created_happened = live_routes_.count(routing_pair) != 0;