Bug 713381 - Add null check on decoder state machine. r=roc

content/media/nsBuiltinDecoder.cpp

@@ -245,6 +245,7 @@ nsresult nsBuiltinDecoder::ScheduleStateMachineThread()
   NS_ASSERTION(NS_IsMainThread(), "Should be on main thread.");
   NS_ASSERTION(mDecoderStateMachine,
                "Must have state machine to start state machine thread");
+  NS_ENSURE_STATE(mDecoderStateMachine);
 
   if (mShuttingDown)
     return NS_OK;
@@ -832,29 +833,19 @@ void nsBuiltinDecoder::ChangeState(PlayState aState)
   }
 
   mPlayState = aState;
-  switch (aState) {
-  case PLAY_STATE_PAUSED:
-    /* No action needed */
-    break;
-  case PLAY_STATE_PLAYING:
-    mDecoderStateMachine->Play();
-    break;
-  case PLAY_STATE_SEEKING:
-    mDecoderStateMachine->Seek(mRequestedSeekTime);
-    mRequestedSeekTime = -1.0;
-    break;
-  case PLAY_STATE_LOADING:
-    /* No action needed */
-    break;
-  case PLAY_STATE_START:
-    /* No action needed */
-    break;
-  case PLAY_STATE_ENDED:
-    /* No action needed */
-    break;
-  case PLAY_STATE_SHUTDOWN:
-    /* No action needed */
-    break;
+  if (mDecoderStateMachine) {
+    switch (aState) {
+    case PLAY_STATE_PLAYING:
+      mDecoderStateMachine->Play();
+      break;
+    case PLAY_STATE_SEEKING:
+      mDecoderStateMachine->Seek(mRequestedSeekTime);
+      mRequestedSeekTime = -1.0;
+      break;
+    default:
+      /* No action needed */
+      break;
+    }
   }
   mReentrantMonitor.NotifyAll();
 }
@@ -973,7 +964,9 @@ void nsBuiltinDecoder::Resume(bool aForceBuffering)
   }
   if (aForceBuffering) {
     ReentrantMonitorAutoEnter mon(mReentrantMonitor);
-    mDecoderStateMachine->StartBuffering();
+    if (mDecoderStateMachine) {
+      mDecoderStateMachine->StartBuffering();
+    }
   }
 }