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

chrome/browser/metrics/thread_watcher.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file defines a WatchDog thread that monitors the responsiveness of other
 // browser threads like UI, IO, DB, FILE and CACHED threads. It also defines
 // ThreadWatcher class which performs health check on threads that would like to
 // be watched. This file also defines ThreadWatcherList class that has list of
 // all active ThreadWatcher objects.
 //
@@ skipping 200 matching lines @@
   // got no response (GotNoResponse) from the watched thread. Count includes the
   // thread that got no response.
   base::Histogram* unresponsive_count_histogram_;
 
   // This counter tracks the unresponsiveness of watched thread. If this value
   // is zero then watched thread has responded with a pong message. This is
   // incremented by 1 when we got no response (GotNoResponse) from the watched
   // 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.
   ScopedRunnableMethodFactory<ThreadWatcher> method_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ThreadWatcher);
 };
 
 // Class with a list of all active thread watchers.  A thread watcher is active
 // if it has been registered, which includes determing the histogram name. This
@@ skipping 130 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(WatchDogThread);
 };
 
 // DISABLE_RUNNABLE_METHOD_REFCOUNT is a convenience macro for disabling
 // refcounting of ThreadWatcher and ThreadWatcherList classes.
 DISABLE_RUNNABLE_METHOD_REFCOUNT(ThreadWatcher);
 DISABLE_RUNNABLE_METHOD_REFCOUNT(ThreadWatcherList);
 
 #endif  // CHROME_BROWSER_METRICS_THREAD_WATCHER_H_