Bug 670059 - Add some JS engine telemetry counters to measure occurrences of: E4X, __iterator__, mutable __proto__ (r=taras,waldo)

js/src/jsiter.cpp

@@ -338,6 +338,8 @@ GetPropertyNames(JSContext *cx, JSObject *obj, uintN flags, AutoIdVector *props)
 
 }
 
+size_t sCustomIteratorCount = 0;
+
 static inline bool
 GetCustomIterator(JSContext *cx, JSObject *obj, uintN flags, Value *vp)
 {
@@ -352,6 +354,9 @@ GetCustomIterator(JSContext *cx, JSObject *obj, uintN flags, Value *vp)
         return true;
     }
 
+    if (!cx->runningWithTrustedPrincipals())
+        ++sCustomIteratorCount;
+
     /* Otherwise call it and return that object. */
     LeaveTrace(cx);
     Value arg = BooleanValue((flags & JSITER_FOREACH) == 0);