Bug 979047, part 3 - Make sure we trigger a GC after a current ICC when we poke the GC. r=smaug

dom/base/nsJSEnvironment.cpp

@@ -2504,6 +2504,13 @@ nsJSContext::PokeGC(JS::gcreason::Reason aReason, int aDelay)
     return;
   }
 
+  if (sICCTimer) {
+    // Make sure GC is called after the current CC completes.
+    // No need to set sNeedsFullCC because we are currently running a CC.
+    sNeedsGCAfterCC = true;
+    return;
+  }
+
   CallCreateInstance("@mozilla.org/timer;1", &sGCTimer);
 
   if (!sGCTimer) {