Work in progress: allow pause-on-exceptions to work in Object.observe callbacks

src/object-observe.js

Index: src/object-observe.js
diff --git a/src/object-observe.js b/src/object-observe.js
index 3af2d512075c15bb4294970ab7eadf8a92a886ab..d034bd0912b9e127f2219e45bfd13c21306ae6c2 100644
--- a/src/object-observe.js
+++ b/src/object-observe.js
@@ -571,8 +571,13 @@ function CallbackDeliverPending(callback) {
   %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;
 }