[futex] Allow debugger to break in the middle of a futexWait

src/debug/debug.cc

Index: src/debug/debug.cc
diff --git a/src/debug/debug.cc b/src/debug/debug.cc
index 99036d71e7e7c6df559e192591ff1d36598e35ef..028bfe2448d89e3fc6a0102553a3121781800ee7 100644
--- a/src/debug/debug.cc
+++ b/src/debug/debug.cc
@@ -2261,7 +2261,7 @@ MaybeHandle<Object> Debug::Call(Handle<JSFunction> fun, Handle<Object> data) {
 }
 
 
-void Debug::HandleDebugBreak() {
+void Debug::HandleDebugBreak(BreakInNonDebuggableFlag flag) {
   // Ignore debug break during bootstrapping.
   if (isolate_->bootstrapper()->IsActive()) return;
   // Just continue if breaks are disabled.
@@ -2277,7 +2277,9 @@ void Debug::HandleDebugBreak() {
     Object* fun = it.frame()->function();
     if (fun && fun->IsJSFunction()) {
       // Don't stop in builtin functions.
-      if (!JSFunction::cast(fun)->IsSubjectToDebugging()) return;
+      if (!(JSFunction::cast(fun)->IsSubjectToDebugging() ||
+            flag == BreakInNonDebuggable))
+        return;
       GlobalObject* global = JSFunction::cast(fun)->context()->global_object();
       // Don't stop in debugger functions.
       if (IsDebugGlobal(global)) return;