Bug 654015 patch 2: Assert that page is hidden when document disconnects from nsSMILAnimationController. r=bz

content/smil/nsSMILAnimationController.cpp

@@ -94,6 +94,8 @@ nsSMILAnimationController::Disconnect()
   NS_ABORT_IF_FALSE(mDocument, "disconnecting when we weren't connected...?");
   NS_ABORT_IF_FALSE(mRefCnt.get() == 1,
                     "Expecting to disconnect when doc is sole remaining owner");
+  NS_ABORT_IF_FALSE(mPauseState & nsSMILTimeContainer::PAUSE_PAGEHIDE,
+                    "Expecting to be paused for pagehide before disconnect");
 
   StopSampling(GetRefreshDriver());