Make sure that WaitableEvent::TimedWait works fine with large timeouts.

base/synchronization/waitable_event.h

 // Copyright (c) 2012 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.
 
 #ifndef BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_
 #define BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 
@@ skipping 63 matching lines @@
   //   SendToOtherThread(e);
   //   e->Wait();
   //   delete e;
   void Wait();
 
   // Wait up until max_time has passed for the event to be signaled.  Returns
   // true if the event was signaled.  If this method returns false, then it
   // does not necessarily mean that max_time was exceeded.
   //
   // TimedWait can synchronise its own destruction like |Wait|.
+  //
+  // Passing a negative |max_time| is not supported.
   bool TimedWait(const TimeDelta& max_time);
 
 #if defined(OS_WIN)
   HANDLE handle() const { return handle_.Get(); }
 #endif
 
   // Wait, synchronously, on multiple events.
   //   waitables: an array of WaitableEvent pointers
   //   count: the number of elements in @waitables
   //
@@ skipping 83 matching lines @@
 
   scoped_refptr<WaitableEventKernel> kernel_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(WaitableEvent);
 };
 
 }  // namespace base
 
 #endif  // BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_