Respect the system ClearType setting in RenderTextWin.

ui/base/win/singleton_hwnd.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 UI_BASE_WIN_SINGLETON_HWND_H_
+#define UI_BASE_WIN_SINGLETON_HWND_H_
+#pragma once
+
+#include <windows.h>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/callback_forward.h"
+
+template<typename T> struct DefaultSingletonTraits;
+
+namespace ui {
+
+typedef base::Callback<void(HWND, UINT, WPARAM, LPARAM)> WndProcCallback;
+
+// Singleton message-only HWND that allows interested clients to receive WM_*
+// notifications.

[msw, 2012/02/15 00:33:16]

Note that not all WM_* messages are supported; point to doc?

[asvitkine_google, 2012/02/15 15:10:44]

Done.

+class SingletonHwnd {

[msw, 2012/02/15 00:33:16]

Why not use/extend existing code like MessagePumpObserver?

[asvitkine_google, 2012/02/15 15:10:44]

I'm not familiar with that class... from a quick glance at it, it's not really
clear to me how it can help here. Can you elaborate on your suggestion?

[msw, 2012/02/15 19:23:28]

You're creating an HWND to listen for arbitrary WM_* MSGs.
MessagePumpForUI in base/message_pump_win.cc does the same thing.
MessagePumpObservers are called for each WM_* MSG sent to that HWND.
Make CachedFontSmoothingSettings a MessagePumpObserver and nix this class.

+ public:
+  // Singleton getter.

[msw, 2012/02/15 00:33:16]

nit: remove obvious comment.

[asvitkine_google, 2012/02/15 15:10:44]

Done.

+  static SingletonHwnd* GetInstance();
+
+  // Registers a listener callback for WM_* notifications.

[msw, 2012/02/15 00:33:16]

Did you consider using [Add|Remove]Observer terminology?

[asvitkine_google, 2012/02/15 15:10:44]

You're right - I think base/observer_list.h is the right thing to use here.
Thanks.

I've updated the code to use it.

+  void RegisterListener(const WndProcCallback& callback);

[msw, 2012/02/15 00:33:16]

Is there no way to UnregisterListener?

[asvitkine_google, 2012/02/15 15:10:44]

Added.

+
+  // Windows callback for WM_* notifications.
+  void OnWndProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam);
+
+ private:
+  friend struct DefaultSingletonTraits<SingletonHwnd>;
+
+  SingletonHwnd();
+  ~SingletonHwnd();
+
+  // Listener HWND for WM_* notifications.
+  HWND listener_window_;
+
+  // List of registered listener callbacks.
+  std::vector<WndProcCallback> listeners_;
+
+  DISALLOW_COPY_AND_ASSIGN(SingletonHwnd);
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_WIN_SINGLETON_HWND_H_