Force a crash of the browser if IO thread hasn't responded

chrome/browser/metrics/thread_watcher.h

Index: chrome/browser/metrics/thread_watcher.h
===================================================================
--- chrome/browser/metrics/thread_watcher.h	(revision 85503)
+++ chrome/browser/metrics/thread_watcher.h	(working copy)
@@ -218,6 +218,11 @@
   // thread.
   int unresponsive_count_;
 
+  // This is set to true when we would have crashed the browser because the
+  // watched thread hasn't responded atleast 3 times. It is reset to false when
+  // watched thread responds with a pong message.
+  bool hung_processing_complete_;
+
   // We use this factory to create callback tasks for ThreadWatcher object. We
   // use this during ping-pong messaging between WatchDog thread and watched
   // thread.