bug 1436267 fallback from audio callback to system clock driver on error only once r?padenot Usually, mShouldFallbackIfError has been reset to false in DataCallback() before Stop() is called. However, if fallback to a system clock driver due to cubeb error had already occurred, then mShouldFallbackIfError would not have been reset, and Stop() is still called. With mShouldFallbackIfError still true, a cubeb error in stop would have created another fallback thread. I expect that resetting mShouldFallbackIfError in Stop() would also be an effective alternative solution, but resetting on StateCallback() happens earlier, which would be an advantage if any additional errors could possibly be reported to StateCallback(). MozReview-Commit-ID: E9j7PQmS3O4

--- a/dom/media/GraphDriver.cpp
+++ b/dom/media/GraphDriver.cpp
@@ -1035,16 +1035,17 @@ AudioCallbackDriver::DataCallback(const 
 }
 
 void
 AudioCallbackDriver::StateCallback(cubeb_state aState)
 {
   LOG(LogLevel::Debug, ("AudioCallbackDriver State: %d", aState));
 
   if (aState == CUBEB_STATE_ERROR && mShouldFallbackIfError) {
+    mShouldFallbackIfError = false;
     MonitorAutoLock lock(GraphImpl()->GetMonitor());
     RemoveCallback();
     FallbackToSystemClockDriver();
   }
 }
 
 void
 AudioCallbackDriver::MixerCallback(AudioDataValue* aMixedBuffer,