Debugger: naive implementation of "step into Function.prototype.bind".

src/debug.cc

Index: src/debug.cc
diff --git a/src/debug.cc b/src/debug.cc
index 2058d48b71e431bf9a89816dbfc47bcf755f11d5..01f6f398af7ee6d9bfe2482af1f3905a25375d52 100644
--- a/src/debug.cc
+++ b/src/debug.cc
@@ -1223,6 +1223,18 @@ void Debug::FloodWithOneShot(Handle<SharedFunctionInfo> shared) {
 }
 
 
+void Debug::FloodBoundFunctionWithOneShot(Handle<JSFunction> function) {
+  Handle<FixedArray> new_bindings(function->function_bindings());
+  Handle<Object> bindee(new_bindings->get(JSFunction::kBoundFunctionIndex));
+
+  if (!bindee.is_null() && bindee->IsJSFunction() &&
+      !JSFunction::cast(*bindee)->IsBuiltin()) {
+    Handle<SharedFunctionInfo> shared_info(JSFunction::cast(*bindee)->shared());
+    Debug::FloodWithOneShot(shared_info);
+  }
+}
+
+
 void Debug::FloodHandlerWithOneShot() {
   // Iterate through the JavaScript stack looking for handlers.
   StackFrame::Id id = break_frame_id();
@@ -1442,8 +1454,10 @@ void Debug::PrepareStep(StepAction step_action, int step_count) {
           expressions_count - 2 - call_function_arg_count);
       if (fun->IsJSFunction()) {
         Handle<JSFunction> js_function(JSFunction::cast(fun));
-        // Don't step into builtins.
-        if (!js_function->IsBuiltin()) {
+        if (js_function->shared()->bound()) {
+          Debug::FloodBoundFunctionWithOneShot(js_function);
+        } else if (!js_function->IsBuiltin()) {
+          // Don't step into builtins.
           // It will also compile target function if it's not compiled yet.
           FloodWithOneShot(Handle<SharedFunctionInfo>(js_function->shared()));
         }
@@ -1639,8 +1653,11 @@ void Debug::HandleStepIn(Handle<JSFunction> function,
   // Flood the function with one-shot break points if it is called from where
   // step into was requested.
   if (fp == step_in_fp()) {
-    // Don't allow step into functions in the native context.
-    if (!function->IsBuiltin()) {
+    if (function->shared()->bound()) {
+      // Handle Function.prototype.bind
+      Debug::FloodBoundFunctionWithOneShot(function);
+    } else if (!function->IsBuiltin()) {
+      // Don't allow step into functions in the native context.
       if (function->shared()->code() ==
           Isolate::Current()->builtins()->builtin(Builtins::kFunctionApply) ||
           function->shared()->code() ==