Bug 1089643 - don't use decltype. r=smaug

docshell/base/nsDocShell.cpp

@@ -2873,7 +2873,7 @@ nsDocShell::PopProfileTimelineMarkers(JSContext* aCx,
   // If we see an unpaired START, we keep it around for the next call
   // to PopProfileTimelineMarkers.  We store the kept START objects in
   // this array.
-  decltype(mProfileTimelineMarkers) keptMarkers;
+  nsTArray<InternalProfileTimelineMarker*> keptMarkers;
 
   for (uint32_t i = 0; i < mProfileTimelineMarkers.Length(); ++i) {
     ProfilerMarkerTracing* startPayload = static_cast<ProfilerMarkerTracing*>(