Return this in Context::native_context if receiver is a native context.

src/contexts.cc

 // Copyright 2011 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/v8.h"
 
 #include "src/bootstrapper.h"
 #include "src/debug.h"
 #include "src/scopeinfo.h"
 
@@ skipping 67 matching lines @@
 Context* Context::script_context() {
   Context* current = this;
   while (!current->IsScriptContext()) {
     current = current->previous();
   }
   return current;
 }
 
 
 Context* Context::native_context() {
-  // Fast case: the global object for this context has been set.  In
-  // that case, the global object has a direct pointer to the global
-  // context.
-  if (global_object()->IsGlobalObject()) {
-    return global_object()->native_context();
-  }
-
-  // During bootstrapping, the global object might not be set and we
-  // have to search the context chain to find the native context.
-  DCHECK(this->GetIsolate()->bootstrapper()->IsActive());
-  Context* current = this;
-  while (!current->IsNativeContext()) {
-    JSFunction* closure = JSFunction::cast(current->closure());
-    current = Context::cast(closure->context());
-  }
-  return current;
+  // Fast case: the receiver context is already a native context.
+  if (IsNativeContext()) return this;
+  // The global object has a direct pointer to the native context. If the
+  // following DCHECK fails, the native context is probably being accessed
+  // indirectly during bootstrapping. This is unsupported.
+  DCHECK(global_object()->IsGlobalObject());
+  return global_object()->native_context();
 }
 
 
 JSObject* Context::global_proxy() {
   return native_context()->global_proxy_object();
 }
 
 
 void Context::set_global_proxy(JSObject* object) {
   native_context()->set_global_proxy_object(object);
@@ skipping 384 matching lines @@
   // During bootstrapping we allow all objects to pass as global
   // objects. This is necessary to fix circular dependencies.
   return isolate->heap()->gc_state() != Heap::NOT_IN_GC ||
       isolate->bootstrapper()->IsActive() ||
       object->IsGlobalObject();
 }
 #endif
 
 }  // namespace internal
 }  // namespace v8