Make members of Singleton<T> private and only visible to the singleton type.

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 <map>
 #include <string>
 
 #include "base/basictypes.h"
-#include "base/singleton.h"
+#include "base/lazy_instance.h"
 #include "base/values.h"
 #include "chrome/common/extensions/extension_message_bundle.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/url_constants.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"
 
@@ skipping 14 matching lines @@
 
 struct ExtensionData {
   struct PortData {
     int ref_count;  // how many contexts have a handle to this port
     bool disconnected;  // true if this port was forcefully disconnected
     PortData() : ref_count(0), disconnected(false) {}
   };
   std::map<int, PortData> ports;  // port ID -> data
 };
 
+static base::LazyInstance<ExtensionData> g_extension_data(
+    base::LINKER_INITIALIZED);
+
 static bool HasPortData(int port_id) {
-  return Singleton<ExtensionData>::get()->ports.find(port_id) !=
-      Singleton<ExtensionData>::get()->ports.end();
+  return g_extension_data.Get().ports.find(port_id) !=
+      g_extension_data.Get().ports.end();
 }
 
 static ExtensionData::PortData& GetPortData(int port_id) {
-  return Singleton<ExtensionData>::get()->ports[port_id];
+  return g_extension_data.Get().ports[port_id];
 }
 
 static void ClearPortData(int port_id) {
-  Singleton<ExtensionData>::get()->ports.erase(port_id);
+  g_extension_data.Get().ports.erase(port_id);
 }
 
 const char kPortClosedError[] = "Attempting to use a disconnected port object";
 const char* kExtensionDeps[] = { EventBindings::kName };
 
 class ExtensionImpl : public ExtensionBase {
  public:
   ExtensionImpl()
       : ExtensionBase(RendererExtensionBindings::kName,
                       GetStringResource(IDR_RENDERER_EXTENSION_BINDINGS_JS),
@@ skipping 237 matching lines @@
                                        const GURL& event_url) {
   v8::HandleScope handle_scope;
   std::vector< v8::Handle<v8::Value> > argv = ListValueToV8(args);
   EventBindings::CallFunction(extension_id,
                               function_name,
                               argv.size(),
                               &argv[0],
                               renderview,
                               event_url);
 }