Terminate worker threads before detaching main thread.

Source/web/WebKit.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 190 matching lines @@
 
         ASSERT(s_messageLoopInterruptor);
         ThreadState::current()->removeInterruptor(s_messageLoopInterruptor);
         delete s_messageLoopInterruptor;
         s_messageLoopInterruptor = 0;
     }
 
     v8::Isolate* isolate = V8PerIsolateData::mainThreadIsolate();
     V8PerIsolateData::willBeDestroyed(isolate);
 
+    // Make sure we stop WorkerThreads before the main thread's ThreadState
+    // and later shutdown steps starts freeing up resources needed during
+    // worker termination.
+    WorkerThread::terminateAndWaitForAllWorkers();
+
     // Detach the main thread before starting the shutdown sequence
     // so that the main thread won't get involved in a GC during the shutdown.
     ThreadState::detachMainThread();
 
     V8PerIsolateData::destroy(isolate);
 
     shutdownWithoutV8();
 }
 
 void shutdownWithoutV8()
@@ skipping 35 matching lines @@
         channel->state = WTFLogChannelOn;
 #endif // !LOG_DISABLED
 }
 
 void resetPluginCache(bool reloadPages)
 {
     Page::refreshPlugins(reloadPages);
 }
 
 } // namespace blink