Refactor extension bindings to share code, avoid exposing hidden variables

chrome/renderer/extensions/renderer_extension_bindings.cc

 // Copyright (c) 2009 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.
 
 #include "chrome/renderer/extensions/renderer_extension_bindings.h"
 
 #include "app/resource_bundle.h"
 #include "base/basictypes.h"
 #include "base/values.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/renderer/extensions/bindings_utils.h"
 #include "chrome/renderer/extensions/event_bindings.h"
 #include "chrome/renderer/render_thread.h"
 #include "chrome/renderer/render_view.h"
 #include "grit/renderer_resources.h"
 
+using bindings_utils::GetStringResource;
+using bindings_utils::ExtensionBase;
+
 // Message passing API example (in a content script):
 // var extension =
 //    new chrome.Extension('00123456789abcdef0123456789abcdef0123456');
 // var port = extension.connect();
 // port.postMessage('Can you hear me now?');
 // port.onmessage.addListener(function(msg, port) {
 //   alert('response=' + msg);
 //   port.postMessage('I got your reponse');
 // });
 
 namespace {
 
 const char* kExtensionDeps[] = { EventBindings::kName };
 
-class ExtensionImpl : public v8::Extension {
+class ExtensionImpl : public ExtensionBase {
  public:
   ExtensionImpl()
-      : v8::Extension(RendererExtensionBindings::kName,
+      : ExtensionBase(RendererExtensionBindings::kName,
                       GetStringResource<IDR_RENDERER_EXTENSION_BINDINGS_JS>(),
                       arraysize(kExtensionDeps), kExtensionDeps) {
   }
   ~ExtensionImpl() {}
 
   virtual v8::Handle<v8::FunctionTemplate> GetNativeFunction(
       v8::Handle<v8::String> name) {
     if (name->Equals(v8::String::New("OpenChannelToExtension"))) {
       return v8::FunctionTemplate::New(OpenChannelToExtension);
     } else if (name->Equals(v8::String::New("PostMessage"))) {
       return v8::FunctionTemplate::New(PostMessage);
     }
-    return v8::Handle<v8::FunctionTemplate>();
+    return ExtensionBase::GetNativeFunction(name);
   }
 
   // Creates a new messaging channel to the given extension.
   static v8::Handle<v8::Value> OpenChannelToExtension(
       const v8::Arguments& args) {
     // Get the current RenderView so that we can send a routed IPC message from
     // the correct source.
-    RenderView* renderview = GetRenderViewForCurrentContext();
+    RenderView* renderview = bindings_utils::GetRenderViewForCurrentContext();
     if (!renderview)
       return v8::Undefined();
 
     if (args.Length() >= 1 && args[0]->IsString()) {
       std::string id = *v8::String::Utf8Value(args[0]->ToString());
       int port_id = -1;
       renderview->Send(new ViewHostMsg_OpenChannelToExtension(
           renderview->routing_id(), id, &port_id));
       return v8::Integer::New(port_id);
     }
     return v8::Undefined();
   }
 
   // Sends a message along the given channel.
   static v8::Handle<v8::Value> PostMessage(const v8::Arguments& args) {
-    RenderView* renderview = GetRenderViewForCurrentContext();
+    RenderView* renderview = bindings_utils::GetRenderViewForCurrentContext();
     if (!renderview)
       return v8::Undefined();
 
     if (args.Length() >= 2 && args[0]->IsInt32() && args[1]->IsString()) {
       int port_id = args[0]->Int32Value();
       std::string message = *v8::String::Utf8Value(args[1]->ToString());
       renderview->Send(new ViewHostMsg_ExtensionPostMessage(
           renderview->routing_id(), port_id, message));
     }
     return v8::Undefined();
@@ skipping 53 matching lines @@
 v8::Extension* RendererExtensionBindings::Get() {
   return new ExtensionImpl();
 }
 
 void RendererExtensionBindings::Invoke(const std::string& function_name,
                                        const ListValue& args) {
   v8::HandleScope handle_scope;
   std::vector< v8::Handle<v8::Value> > argv = ListValueToV8(args);
   EventBindings::CallFunction(function_name, argv.size(), &argv[0]);
 }