Lazily compute boundfunction .name and .length if possible

src/runtime/runtime-debug.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/debug/debug-evaluate.h"
 #include "src/debug/debug-frames.h"
 #include "src/debug/debug-scopes.h"
@@ skipping 1436 matching lines @@
   return isolate->heap()->empty_string();
 }
 
 
 RUNTIME_FUNCTION(Runtime_FunctionGetDebugName) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
 
   CONVERT_ARG_HANDLE_CHECKED(JSReceiver, function, 0);
 
+  Handle<Object> name;
   if (function->IsJSBoundFunction()) {
-    return Handle<JSBoundFunction>::cast(function)->name();
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, name, JSBoundFunction::GetName(
+                           isolate, Handle<JSBoundFunction>::cast(function)));
+  } else {
+    name = JSFunction::GetDebugName(Handle<JSFunction>::cast(function));
   }
-  Handle<Object> name =
-      JSFunction::GetDebugName(Handle<JSFunction>::cast(function));
   return *name;
 }
 
 
 // A testing entry. Returns statement position which is the closest to
 // source_position.
 RUNTIME_FUNCTION(Runtime_GetFunctionCodePositionFromSource) {
   HandleScope scope(isolate);
   CHECK(isolate->debug()->live_edit_enabled());
   DCHECK(args.length() == 2);
@@ skipping 168 matching lines @@
   return Smi::FromInt(isolate->debug()->is_active());
 }
 
 
 RUNTIME_FUNCTION(Runtime_DebugBreakInOptimizedCode) {
   UNIMPLEMENTED();
   return NULL;
 }
 }  // namespace internal
 }  // namespace v8