Trigger debug event on not yet caught exception in promises.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index c508b4a644fb2540caf3c178d11af3ab7841a057..b5301b0a1d3844f8593bc73dddf825a0c278d631 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -5649,6 +5649,20 @@ RUNTIME_FUNCTION(Runtime_DebugPrepareStepInIfStepping) {
 }
 
 
+// Notify the debugger if an expcetion in a promise is not caught (yet).
+RUNTIME_FUNCTION(Runtime_DebugPendingExceptionInPromise) {
+  SealHandleScope shs(isolate);
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  ASSERT(args.length() == 2);
+  HandleScope scope(isolate);
+  CONVERT_ARG_HANDLE_CHECKED(Object, exception, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, promise, 1);
+  isolate->debugger()->OnException(exception, true, promise);
+#endif  // ENABLE_DEBUGGER_SUPPORT
+  return isolate->heap()->undefined_value();
+}
+
+
 // Set a local property, even if it is READ_ONLY.  If the property does not
 // exist, it will be added with attributes NONE.
 RUNTIME_FUNCTION(Runtime_IgnoreAttributesAndSetProperty) {