b=463968 test_wav_ended1.html can fail on slow machines with no audio hardware. r+sr=roc

content/media/video/src/nsAudioStream.cpp

@@ -41,6 +41,7 @@
 #include "prmem.h"
 #include "nsAutoPtr.h"
 #include "nsAudioStream.h"
+#include "nsAlgorithm.h"
 extern "C" {
 #include "sydneyaudio/sydney_audio.h"
 }
@@ -255,8 +256,14 @@ double nsAudioStream::GetTime()
 {
   // If the audio backend failed to open, emulate the current playback
   // position using the system clock.
-  if (!mAudioHandle)
-    return mPaused ? mPauseTime : CurrentTimeInSeconds() - mStartTime;
+  if (!mAudioHandle) {
+    if (mPaused) {
+      return mPauseTime;
+    }
+    float curTime = CurrentTimeInSeconds() - mStartTime;
+    float maxTime = float(mSamplesBuffered) / mRate / mChannels;
+    return NS_MIN(curTime, maxTime);
+  }
 
   int64_t bytes = 0;
 #if defined(WIN32)

content/media/video/src/nsWaveDecoder.cpp

@@ -606,8 +606,14 @@ nsWaveStateMachine::Run()
         monitor.Exit();
         mAudioStream->Drain();
         monitor.Enter();
+        mTimeOffset = mAudioStream->GetTime();
       }
 
+      // Dispose the audio stream early (before SHUTDOWN) so that
+      // GetCurrentTime no longer attempts to query the audio backend for
+      // stream time.
+      CloseAudioStream();
+
       if (mState != STATE_SHUTDOWN) {
         nsCOMPtr<nsIRunnable> event =
           NS_NEW_RUNNABLE_METHOD(nsWaveDecoder, mDecoder, PlaybackEnded);