Implement lazy JS module initialisation.

chrome/renderer/module_system.h

 // Copyright (c) 2012 The Chromium 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 CHROME_RENDERER_MODULE_SYSTEM_H_
 #define CHROME_RENDERER_MODULE_SYSTEM_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "base/memory/linked_ptr.h"
@@ skipping 47 matching lines @@
 
   // Executes |code| in the current context with |name| as the filename.
   void RunString(const std::string& code, const std::string& name);
 
   // When false |natives_enabled_| causes calls to GetNative() (the basis of
   // requireNative() in JS) to throw an exception.
   void set_natives_enabled(bool natives_enabled) {
     natives_enabled_ = natives_enabled;
   }
 
-  // Create an object which delegates all property accesses to the object that
-  // |source| evaluates to. The source is evaluated lazily on access to any of
-  // the object's properties.
-  static v8::Handle<v8::Object> CreateLazyObject(const std::string& source_name,
-                                                 v8::Handle<v8::String> source);
+  static v8::Handle<v8::Value> GetterRouter(v8::Local<v8::String> property,

[not at google - send to devlin, 2012/03/22 00:35:53]

Documentation.

Though does this need to be public? Does it even need to be in the header file?

[koz (OOO until 15th September), 2012/03/22 01:13:01]

I've made it private, but it does need to be a member of this class, and
therefore in the header file, because it calls private methods on ModuleSystem.

+                                            const v8::AccessorInfo& info);
+
+  // Make |object|.|field| lazily evaluate to the result of
+  // require(|module_name|)[|module_field|].
+  void SetLazyField(v8::Handle<v8::Object> object,
+                    const std::string& field,
+                    const std::string& module_name,
+                    const std::string& module_field);
 
  private:
   typedef std::map<std::string, linked_ptr<NativeHandler> > NativeHandlerMap;
 
   // Ensure that require_ has been evaluated from require.js.
   void EnsureRequireLoaded();
 
   // Run |code| in the current context with the name |name| used for stack
   // traces.
   v8::Handle<v8::Value> RunString(v8::Handle<v8::String> code,
@@ skipping 15 matching lines @@
   v8::Handle<v8::Value> ThrowException(const std::string& message);
 
   // A map from module names to the JS source for that module. GetSource()
   // performs a lookup on this map.
   SourceMap* source_map_;
   NativeHandlerMap native_handler_map_;
   bool natives_enabled_;
 };
 
 #endif  // CHROME_RENDERER_MODULE_SYSTEM_H_