Bug 1306235 - XHR should set lengthComputable only if total value is set, r=wisniewskit, r=smaug

dom/xhr/XMLHttpRequestMainThread.cpp

@@ -1334,7 +1334,7 @@ XMLHttpRequestMainThread::DispatchProgressEvent(DOMEventTargetHelper* aTarget,
   ProgressEventInit init;
   init.mBubbles = false;
   init.mCancelable = false;
-  init.mLengthComputable = aTotal != 0; // XHR spec step 6.1
+  init.mLengthComputable = aTotal != -1; // XHR spec step 6.1
   init.mLoaded = aLoaded;
   init.mTotal = (aTotal == -1) ? 0 : aTotal;