Use CondVar+Lock+bool instead of WaitableEvent for MessagePumpDefault on posix

base/message_loop/message_pump_default.h

Index: base/message_loop/message_pump_default.h
diff --git a/base/message_loop/message_pump_default.h b/base/message_loop/message_pump_default.h
index 19e720013fd69ca635bfa9801d114236562d83cc..581f308a9de6fc7da523d822e12bd1ac4904080c 100644
--- a/base/message_loop/message_pump_default.h
+++ b/base/message_loop/message_pump_default.h
@@ -7,6 +7,8 @@
 
 #include "base/base_export.h"
 #include "base/message_loop/message_pump.h"
+#include "base/synchronization/condition_variable.h"
+#include "base/synchronization/lock.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/time/time.h"
 
@@ -24,11 +26,23 @@ class BASE_EXPORT MessagePumpDefault : public MessagePump {
   virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time) OVERRIDE;
 
  private:
+  void Wait();
+  void TimedWait(const TimeDelta& max_time);
+  void Signal();
+
   // This flag is set to false when Run should return.
   bool keep_running_;
 
+#if defined(OS_WIN)
   // Used to sleep until there is more work to do.
   WaitableEvent event_;
+#elif defined(OS_POSIX)
+  Lock lock_;  // Protects needs_wake_up_ and cv_;
+  bool needs_wake_up_;
+  ConditionVariable cv_;
+#else
+#error Need implementation for your platform
+#endif
 
   // The time at which we should call DoDelayedWork.
   TimeTicks delayed_work_time_;