[debugger] remove frame argument for prepare step.

src/runtime/runtime-debug.cc

Index: src/runtime/runtime-debug.cc
diff --git a/src/runtime/runtime-debug.cc b/src/runtime/runtime-debug.cc
index 56d15581d78796848d8a7a48e35f429939371bb1..c196ee28da760de360a7a3dc68a458cb512d1c92 100644
--- a/src/runtime/runtime-debug.cc
+++ b/src/runtime/runtime-debug.cc
@@ -1212,7 +1212,7 @@ RUNTIME_FUNCTION(Runtime_IsBreakOnException) {
 //          of frames to step down.
 RUNTIME_FUNCTION(Runtime_PrepareStep) {
   HandleScope scope(isolate);
-  DCHECK(args.length() == 4);
+  DCHECK(args.length() == 3);
   CONVERT_NUMBER_CHECKED(int, break_id, Int32, args[0]);
   RUNTIME_ASSERT(isolate->debug()->CheckExecutionState(break_id));
 
@@ -1220,15 +1220,6 @@ RUNTIME_FUNCTION(Runtime_PrepareStep) {
     return isolate->Throw(isolate->heap()->illegal_argument_string());
   }
 
-  CONVERT_NUMBER_CHECKED(int, wrapped_frame_id, Int32, args[3]);
-
-  StackFrame::Id frame_id;
-  if (wrapped_frame_id == 0) {
-    frame_id = StackFrame::NO_ID;
-  } else {
-    frame_id = DebugFrameHelper::UnwrapFrameId(wrapped_frame_id);
-  }
-
   // Get the step action and check validity.
   StepAction step_action = static_cast<StepAction>(NumberToInt32(args[1]));
   if (step_action != StepIn && step_action != StepNext &&
@@ -1236,11 +1227,6 @@ RUNTIME_FUNCTION(Runtime_PrepareStep) {
     return isolate->Throw(isolate->heap()->illegal_argument_string());
   }
 
-  if (frame_id != StackFrame::NO_ID && step_action != StepNext &&
-      step_action != StepOut) {
-    return isolate->ThrowIllegalOperation();
-  }
-
   // Get the number of steps.
   int step_count = NumberToInt32(args[2]);
   if (step_count < 1) {
@@ -1252,7 +1238,7 @@ RUNTIME_FUNCTION(Runtime_PrepareStep) {
 
   // Prepare step.
   isolate->debug()->PrepareStep(static_cast<StepAction>(step_action),
-                                step_count, frame_id);
+                                step_count);
   return isolate->heap()->undefined_value();
 }