Bug 798491: Add an option to stick all chrome JSMs/JS components in the same compartment. r=mrbkap,philikon

toolkit/components/perf/PerfMeasurement.cpp

@@ -7,6 +7,7 @@
 #include "jsperf.h"
 #include "mozilla/ModuleUtils.h"
 #include "nsMemory.h"
+#include "mozilla/Preferences.h"
 
 #define JSPERF_CONTRACTID \
   "@mozilla.org/jsperf;1"
@@ -58,6 +59,10 @@ InitAndSealPerfMeasurementClass(JSContext* cx, JSObject* global)
   if (!JS::RegisterPerfMeasurement(cx, global))
     return false;
 
+  // Can't freeze our global if it's shared.
+  if (Preferences::GetBool("jsloader.reuseGlobal"))
+    return true;
+
   // Seal up Object, Function, and Array and their prototypes.  (This single
   // object instance is shared amongst everyone who imports the jsperf module.)
   if (!SealObjectAndPrototype(cx, global, "Object") ||