Merged r12019 into 3.10 branch.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 6163ca8fa37152f28eb47cce131f01c6056590e8..9e9be41f619008e6c137d6a12aacc00b921c4672 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -4730,21 +4730,28 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_StoreArrayLiteralElement) {
 // Check whether debugger and is about to step into the callback that is passed
 // to a built-in function such as Array.forEach.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugCallbackSupportsStepping) {
-  if (!isolate->IsDebuggerActive()) return isolate->heap()->false_value();
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  if (!isolate->IsDebuggerActive() || !isolate->debug()->StepInActive()) {
+    return isolate->heap()->false_value();
+  }
   CONVERT_ARG_CHECKED(Object, callback, 0);
   // We do not step into the callback if it's a builtin or not even a function.
   if (!callback->IsJSFunction() || JSFunction::cast(callback)->IsBuiltin()) {
     return isolate->heap()->false_value();
   }
   return isolate->heap()->true_value();
+#else
+  return isolate->heap()->false_value();
+#endif  // ENABLE_DEBUGGER_SUPPORT
 }
 
 
 // Set one shot breakpoints for the callback function that is passed to a
 // built-in function such as Array.forEach to enable stepping into the callback.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugPrepareStepInIfStepping) {
+#ifdef ENABLE_DEBUGGER_SUPPORT
   Debug* debug = isolate->debug();
-  if (!debug->IsStepping()) return NULL;
+  if (!debug->IsStepping()) return isolate->heap()->undefined_value();
   CONVERT_ARG_CHECKED(Object, callback, 0);
   HandleScope scope(isolate);
   Handle<SharedFunctionInfo> shared_info(JSFunction::cast(callback)->shared());
@@ -4753,7 +4760,8 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugPrepareStepInIfStepping) {
   // again, we need to clear the step out at this point.
   debug->ClearStepOut();
   debug->FloodWithOneShot(shared_info);
-  return NULL;
+#endif  // ENABLE_DEBUGGER_SUPPORT
+  return isolate->heap()->undefined_value();
 }