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diff --git a/third_party/libjingle/files/talk/base/signalthread.h b/third_party/libjingle/files/talk/base/signalthread.h
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+++ b/third_party/libjingle/files/talk/base/signalthread.h
@@ -0,0 +1,125 @@
+#ifndef _SIGNALTHREAD_H_
+#define _SIGNALTHREAD_H_
+
+#include "talk/base/thread.h"
+#include "talk/base/sigslot.h"
+
+namespace talk_base {
+
+///////////////////////////////////////////////////////////////////////////////
+// SignalThread - Base class for worker threads.  The main thread should call
+//  Start() to begin work, and then follow one of these models:
+//   Normal: Wait for SignalWorkDone, and then call Release to destroy.
+//   Cancellation: Call Release(true), to abort the worker thread.
+//   Fire-and-forget: Call Release(false), which allows the thread to run to
+//    completion, and then self-destruct without further notification.
+//   Periodic tasks: Wait for SignalWorkDone, then eventually call Start()
+//    again to repeat the task. When the instance isn't needed anymore,
+//    call Release. DoWork, OnWorkStart and OnWorkStop are called again,
+//    on a new thread.
+//  The subclass should override DoWork() to perform the background task.  By
+//   periodically calling ContinueWork(), it can check for cancellation.
+//   OnWorkStart and OnWorkDone can be overridden to do pre- or post-work
+//   tasks in the context of the main thread.
+///////////////////////////////////////////////////////////////////////////////
+
+class SignalThread : public sigslot::has_slots<>, protected MessageHandler {
+public:
+  SignalThread();
+
+  // Context: Main Thread.  Call before Start to change the worker's priority.
+  void SetPriority(ThreadPriority priority);
+
+  // Context: Main Thread.  Call to begin the worker thread.
+  void Start();
+
+  // Context: Main Thread.  If the worker thread is not running, deletes the
+  // object immediately.  Otherwise, asks the worker thread to abort processing,
+  // and schedules the object to be deleted once the worker exits.
+  // SignalWorkDone will not be signalled.  If wait is true, does not return
+  // until the thread is deleted.
+  void Destroy(bool wait);
+
+  // Context: Main Thread.  If the worker thread is complete, deletes the
+  // object immediately.  Otherwise, schedules the object to be deleted once
+  // the worker thread completes.  SignalWorkDone will be signalled.
+  void Release();
+
+  // Context: Main Thread.  Signalled when work is complete.
+  sigslot::signal1<SignalThread *> SignalWorkDone;
+
+  enum { ST_MSG_WORKER_DONE, ST_MSG_FIRST_AVAILABLE };
+
+protected:
+  virtual ~SignalThread();
+
+  // Context: Main Thread.  Subclass should override to do pre-work setup.
+  virtual void OnWorkStart() { }
+
+  // Context: Worker Thread.  Subclass should override to do work.
+  virtual void DoWork() = 0;
+
+  // Context: Worker Thread.  Subclass should call periodically to 
+  // dispatch messages and determine if the thread should terminate.
+  bool ContinueWork();
+
+  // Context: Worker Thread.  Subclass should override when extra work is
+  // needed to abort the worker thread.
+  virtual void OnWorkStop() { }
+
+  // Context: Main Thread.  Subclass should override to do post-work cleanup.
+  virtual void OnWorkDone() { }
+ 
+  // Context: Any Thread.  If subclass overrides, be sure to call the base
+  // implementation.  Do not use (message_id < ST_MSG_FIRST_AVAILABLE)
+  virtual void OnMessage(Message *msg);
+
+private:
+  friend class Worker;
+  class Worker : public Thread {
+  public:
+    SignalThread* parent_;
+    virtual void Run() { parent_->Run(); }
+  };
+
+  class EnterExit {
+    friend class SignalThread;
+   
+    SignalThread * t_;
+   
+    EnterExit(SignalThread * t) : t_(t) {
+      t_->cs_.Enter();
+      t_->refcount_ += 1;
+    }
+    ~EnterExit() {
+      bool d = (0 == (--(t_->refcount_)));
+      t_->cs_.Leave();
+      if (d)
+        delete t_;
+    }
+  };
+
+  friend class EnterExit;
+ 
+  CriticalSection cs_;
+  int refcount_;
+
+  void Run();
+  void OnMainThreadDestroyed();
+
+  Thread* main_;
+  Worker worker_;
+  enum State {
+    kInit,            // Initialized, but not started
+    kRunning,         // Started and doing work
+    kReleasing,       // Same as running, but to be deleted when work is done
+    kComplete,        // Work is done
+    kStopping,        // Work is being interrupted
+  } state_;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+}  // namespace talk_base
+
+#endif  // _SIGNALTHREAD_H_