Implement first part of supporting global extension commands.

ui/gfx/win/singleton_hwnd.cc

 // 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.
 
 #include "ui/gfx/win/singleton_hwnd.h"
 
 #include "base/memory/singleton.h"
 #include "base/message_loop/message_loop.h"
 
 namespace gfx {
 
 // static
 SingletonHwnd* SingletonHwnd::GetInstance() {
   return Singleton<SingletonHwnd>::get();
 }
 
+void SingletonHwnd::Init() {
+  if (!base::MessageLoop::current() ||
+      base::MessageLoop::current()->type() != base::MessageLoop::TYPE_UI) {
+    // Creating this window in (e.g.) a renderer inhibits shutdown on
+    // Windows. See http://crbug.com/230122 and http://crbug.com/236039.
+    DLOG(ERROR) << "Cannot create windows on non-UI thread!";
+    return;
+  }
+  WindowImpl::Init(NULL, Rect());
+}
+
 void SingletonHwnd::AddObserver(Observer* observer) {
-  if (!hwnd()) {
-    if (!base::MessageLoop::current() ||
-        base::MessageLoop::current()->type() != base::MessageLoop::TYPE_UI) {
-      // Creating this window in (e.g.) a renderer inhibits shutdown on
-      // Windows. See http://crbug.com/230122 and http://crbug.com/236039.
-      DLOG(ERROR) << "Cannot create windows on non-UI thread!";
-      return;
-    }
-    WindowImpl::Init(NULL, Rect());
-  }
+  if (!hwnd())
+    Init();
   observer_list_.AddObserver(observer);
 }
 
 void SingletonHwnd::RemoveObserver(Observer* observer) {
   if (!hwnd())
     return;
   observer_list_.RemoveObserver(observer);
 }
 
 BOOL SingletonHwnd::ProcessWindowMessage(HWND window,
                                          UINT message,
                                          WPARAM wparam,
                                          LPARAM lparam,
                                          LRESULT& result,
                                          DWORD msg_map_id) {
   FOR_EACH_OBSERVER(Observer,
                     observer_list_,
                     OnWndProc(window, message, wparam, lparam));
   return false;
 }
 
 SingletonHwnd::SingletonHwnd() {
 }
 
 SingletonHwnd::~SingletonHwnd() {
 }
 
 }  // namespace gfx