Verify if GPU message pump is signaled when it hangs in WaitForWork

base/message_loop/message_pump.h

Index: base/message_loop/message_pump.h
diff --git a/base/message_loop/message_pump.h b/base/message_loop/message_pump.h
index c53be8041096602d0b70e4f0dff2a7db0426d710..af8ed41f278784b5bde4548e6aae973b627b58ad 100644
--- a/base/message_loop/message_pump.h
+++ b/base/message_loop/message_pump.h
@@ -124,6 +124,15 @@ class BASE_EXPORT MessagePump : public NonThreadSafe {
 
   // Sets the timer slack to the specified value.
   virtual void SetTimerSlack(TimerSlack timer_slack);
+
+#if defined(OS_WIN)
+  // TODO (stanisc): crbug.com/596190: Remove this after the signaling issue
+  // has been investigated.
+  // This should be used for diagnostic only. If message pump wake-up mechanism
+  // is based on auto-reset event this call would reset the event to unset
+  // state.
+  virtual bool WasSignaled();
+#endif
 };
 
 }  // namespace base