Cache experimental natives sources as external strings.

src/bootstrapper.h

 // 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.
 
 #ifndef V8_BOOTSTRAPPER_H_
 #define V8_BOOTSTRAPPER_H_
 
 #include "src/factory.h"
 
 namespace v8 {
@@ skipping 69 matching lines @@
       v8::Handle<v8::ObjectTemplate> global_object_template,
       v8::ExtensionConfiguration* extensions);
 
   // Detach the environment from its outer global object.
   void DetachGlobal(Handle<Context> env);
 
   // Traverses the pointers for memory management.
   void Iterate(ObjectVisitor* v);
 
   // Accessor for the native scripts source code.
-  Handle<String> NativesSourceLookup(int index);
+  template <class Source>
+  Handle<String> SourceLookup(int index);
 
   // Tells whether bootstrapping is active.
   bool IsActive() const { return nesting_ != 0; }
 
   // Support for thread preemption.
   static int ArchiveSpacePerThread();
   char* ArchiveState(char* to);
   char* RestoreState(char* from);
   void FreeThreadResources();
 
@@ skipping 52 matching lines @@
   size_t length() const override { return length_; }
 
  private:
   const char* data_;
   size_t length_;
 };
 
 }}  // namespace v8::internal
 
 #endif  // V8_BOOTSTRAPPER_H_