Allow uncaught exception messaging in Object.observe callbacks.

src/object-observe.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 "use strict";
 
 // Overview:
 //
 // This file contains all of the routing and accounting for Object.observe.
 // User code will interact with these mechanisms via the Object.observe APIs
@@ skipping 549 matching lines @@
 
   // Clear the pending change records from callback and return it to its
   // "optimized" state.
   var priority = callbackInfo.priority;
   CallbackInfoSet(callback, priority);
 
   var pendingObservers = GetPendingObservers();
   if (!IS_NULL(pendingObservers))
     delete pendingObservers[priority];
 
+  // TODO: combine the following runtime calls for perf optimization.
   var delivered = [];
   %MoveArrayContents(callbackInfo, delivered);
+  %DeliverObservationChangeRecords(callback, delivered);
 
-  try {
-    %_CallFunction(UNDEFINED, delivered, callback);
-  } catch (ex) {}  // TODO(rossberg): perhaps log uncaught exceptions.
   return true;
 }
 
 function ObjectDeliverChangeRecords(callback) {
   if (!IS_SPEC_FUNCTION(callback))
     throw MakeTypeError("observe_non_function", ["deliverChangeRecords"]);
 
   while (CallbackDeliverPending(callback)) {}
 }
 
@@ skipping 19 matching lines @@
     "observe", ArrayObserve,
     "unobserve", ArrayUnobserve
   ));
   InstallFunctions(notifierPrototype, DONT_ENUM, $Array(
     "notify", ObjectNotifierNotify,
     "performChange", ObjectNotifierPerformChange
   ));
 }
 
 SetupObjectObserve();