[runtime] Introduce dedicated JSBoundFunction to represent bound functions.

src/accessors.cc

 // Copyright 2012 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/accessors.h"
 
 #include "src/api.h"
 #include "src/contexts.h"
 #include "src/deoptimizer.h"
 #include "src/execution.h"
@@ skipping 1311 matching lines @@
   // If caller is a built-in function and caller's caller is also built-in,
   // use that instead.
   JSFunction* potential_caller = caller;
   while (potential_caller != NULL && potential_caller->shared()->IsBuiltin()) {
     caller = potential_caller;
     potential_caller = it.next();
   }
   if (!caller->shared()->native() && potential_caller != NULL) {
     caller = potential_caller;
   }
-  // If caller is bound, return null. This is compatible with JSC, and
-  // allows us to make bound functions use the strict function map
-  // and its associated throwing caller and arguments.
-  if (caller->shared()->bound()) {
-    return MaybeHandle<JSFunction>();
-  }
   // Censor if the caller is not a sloppy mode function.
   // Change from ES5, which used to throw, see:
   // https://bugs.ecmascript.org/show_bug.cgi?id=310
   if (is_strict(caller->shared()->language_mode())) {
     return MaybeHandle<JSFunction>();
   }
   // Don't return caller from another security context.
   if (!AllowAccessToFunction(isolate->context(), caller)) {
     return MaybeHandle<JSFunction>();
   }
@@ skipping 120 matching lines @@
   Handle<Object> getter = v8::FromCData(isolate, &ModuleGetExport);
   Handle<Object> setter = v8::FromCData(isolate, &ModuleSetExport);
   info->set_getter(*getter);
   if (!(attributes & ReadOnly)) info->set_setter(*setter);
   return info;
 }
 
 
 }  // namespace internal
 }  // namespace v8