Abandon prerenders upon render thread shutdown.

third_party/WebKit/Source/web/WebKit.cpp

Index: third_party/WebKit/Source/web/WebKit.cpp
diff --git a/third_party/WebKit/Source/web/WebKit.cpp b/third_party/WebKit/Source/web/WebKit.cpp
index f0ac13e62a2b6599a8aee2b4310dc3223c05ec14..d5319e564d052308f44fa5f328d4e3072bc96162 100644
--- a/third_party/WebKit/Source/web/WebKit.cpp
+++ b/third_party/WebKit/Source/web/WebKit.cpp
@@ -42,6 +42,7 @@
 #include "platform/Logging.h"
 #include "platform/heap/Heap.h"
 #include "public/platform/Platform.h"
+#include "public/platform/WebPrerenderingSupport.h"
 #include "public/platform/WebThread.h"
 #include "wtf/Assertions.h"
 #include "wtf/WTF.h"
@@ -110,6 +111,9 @@ void shutdown()
 
     modulesInitializer().shutdown();
 
+    if (WebPrerenderingSupport* prerender = WebPrerenderingSupport::current())
+        prerender->detachRenderer();
+
     Platform::shutdown();
 }