Work in progress: allow pause-on-exceptions to work 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 553 matching lines @@
   CallbackInfoSet(callback, priority);
 
   var pendingObservers = GetPendingObservers();
   if (!IS_NULL(pendingObservers))
     delete pendingObservers[priority];
 
   var delivered = [];
   %MoveArrayContents(callbackInfo, delivered);
 
   try {
+    %DebugPushPromise(null);

[aandrey, 2014/10/30 10:53:01]

But should not we patch Isolate::DoThrow() instead?

Maybe we just call smth like %SetVerboseNextTryCatch() before entering the
try-catch block to make it alike the verbose v8::TryCatch? Message reporting and
debug event will work naturally w/o any changes.

     %_CallFunction(UNDEFINED, delivered, callback);
-  } catch (ex) {}  // TODO(rossberg): perhaps log uncaught exceptions.
+  } catch (ex) {
+    // TODO(rossberg): perhaps log uncaught exceptions.
+  } finally {
+    %DebugPopPromise();
+  }
   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();