Bug 766886 - Cleanup plugin streams earlier to avoid shutdown leak. r=bsmedberg

dom/plugins/base/nsNPAPIPluginStreamListener.cpp

@@ -208,14 +208,17 @@ nsNPAPIPluginStreamListener::CleanUpStream(NPReason reason)
 
   // Seekable streams have an extra addref when they are created which must
   // be matched here.
-  if (NP_SEEK == mStreamType)
+  if (NP_SEEK == mStreamType && mStreamStarted)
     NS_RELEASE_THIS();
 
+  if (mStreamListenerPeer) {
+    mStreamListenerPeer->CancelRequests(NS_BINDING_ABORTED);
+    mStreamListenerPeer = nullptr;
+  }
+
   if (!mInst || !mInst->CanFireNotifications())
     return rv;
   
-  mStreamListenerPeer = nullptr;
-  
   PluginDestructionGuard guard(mInst);
 
   nsNPAPIPlugin* plugin = mInst->GetPlugin();
@@ -280,7 +283,7 @@ nsNPAPIPluginStreamListener::CallURLNotify(NPReason reason)
 nsresult
 nsNPAPIPluginStreamListener::OnStartBinding(nsPluginStreamListenerPeer* streamPeer)
 {
-  if (!mInst || !mInst->CanFireNotifications())
+  if (!mInst || !mInst->CanFireNotifications() || mStreamCleanedUp)
     return NS_ERROR_FAILURE;
 
   PluginDestructionGuard guard(mInst);