Abandon prerenders upon render thread shutdown.

third_party/WebKit/public/platform/WebPrerenderingSupport.h

Index: third_party/WebKit/public/platform/WebPrerenderingSupport.h
diff --git a/third_party/WebKit/public/platform/WebPrerenderingSupport.h b/third_party/WebKit/public/platform/WebPrerenderingSupport.h
index d1c553353050b0033feb042b2211de44f023ff7d..5d51c50be56070e0765a300df79439924beb0ba7 100644
--- a/third_party/WebKit/public/platform/WebPrerenderingSupport.h
+++ b/third_party/WebKit/public/platform/WebPrerenderingSupport.h
@@ -54,6 +54,10 @@ public:
     // wanted, and we may end up using it after, for instance, a short redirect chain.
     virtual void abandon(const WebPrerender&) = 0;
 
+    // The renderer is shutting down, the prerendering layer is not allowed to
+    // access Blink objects after this notification.
+    virtual void detachRenderer() = 0;
+
 protected:
     WebPrerenderingSupport() { }
     virtual ~WebPrerenderingSupport() { }