Plumb listenerIDs correctly for events that clobber chrome.Event.prototype.dispatch.

chrome/renderer/extensions/chrome_v8_context_set.cc

Index: chrome/renderer/extensions/chrome_v8_context_set.cc
diff --git a/chrome/renderer/extensions/chrome_v8_context_set.cc b/chrome/renderer/extensions/chrome_v8_context_set.cc
index dfe3d85fa532b03c1ffa89f8a1609598f7e8104a..808e46456f14463cb70b1d69772e59ad1ce1e180 100644
--- a/chrome/renderer/extensions/chrome_v8_context_set.cc
+++ b/chrome/renderer/extensions/chrome_v8_context_set.cc
@@ -145,15 +145,5 @@ void ChromeV8ContextSet::DispatchChromeHiddenMethod(
     v8::Handle<v8::Value> retval;
     (*it)->CallChromeHiddenMethod(
         method_name, v8_arguments.size(), &v8_arguments[0], &retval);
-    // In debug, the js will validate the event parameters and return a
-    // string if a validation error has occured.
-    // TODO(rafaelw): Consider only doing this check if function_name ==
-    // "Event.dispatchJSON".
-#ifndef NDEBUG
-    if (!retval.IsEmpty() && !retval->IsUndefined()) {
-      std::string error = *v8::String::AsciiValue(retval);
-      DCHECK(false) << error;
-    }
-#endif
   }
 }