GTK: Support Ambiance/Radiance and Dust button ordering.

chrome/browser/gtk/gconf_titlebar_listener.h

Index: chrome/browser/gtk/gconf_titlebar_listener.h
diff --git a/chrome/browser/gtk/gconf_titlebar_listener.h b/chrome/browser/gtk/gconf_titlebar_listener.h
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index 0000000000000000000000000000000000000000..b345f9a392ad2a7a5dc61ff711bc9b98bcddf988
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+++ b/chrome/browser/gtk/gconf_titlebar_listener.h
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+// Copyright (c) 2009 The Chromium Authors. All rights reserved.

[Evan Stade, 2010/05/13 20:30:16]

nit: year

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_GTK_GCONF_TITLEBAR_LISTENER_H_
+#define CHROME_BROWSER_GTK_GCONF_TITLEBAR_LISTENER_H_
+
+#include <gconf/gconf-client.h>
+#include <gtk/gtk.h>
+
+#include <set>
+#include <string>
+
+#include "app/gtk_signal.h"
+#include "base/singleton.h"
+
+class BrowserTitlebar;
+
+// On GNOME desktops, subscribes to the gconf key which controlls button order.
+// Everywhere else, SetTiltebarButtons() just calls back into BrowserTitlebar
+// with the default ordering.
+//
+// Meant to be used as a Singleton through base/singleton.h's interface.
+class GConfTitlebarListener {
+ public:
+  // Sets the current titlebar button order. On GNOME desktops, also subscribes
+  // to further notifications when this changes.
+  void SetTitlebarButtons(BrowserTitlebar* titlebar);
+
+  // Removes |titlebar| from the list of objects observing button order change
+  // notifications.
+  void RemoveObserver(BrowserTitlebar* titlebar);
+
+ private:
+  // Private constructor to enforce singleton access.
+  GConfTitlebarListener();
+
+  // Called whenever the metacity key changes.
+  CHROMEG_CALLBACK_2(GConfTitlebarListener, void, OnChangeNotification,
+                     GConfClient*, guint, GConfEntry*);
+
+  // Checks |error|. On error, prints out a message and closes the connection
+  // to GConf and reverts to default mode.
+  bool HandleGError(GError* error, const char* key);
+
+  // Parses the return data structure from GConf, falling back to the default
+  // value on any error.
+  void ParseAndStoreValue(GConfValue* gconf_value);
+
+  // Pointer to our gconf context. NULL if we aren't on a desktop that uses
+  // gconf.
+  GConfClient* client_;
+
+  // The current button ordering as heard from gconf.
+  std::string current_value_;
+
+  // BrowserTitlebar objects which have subscribed to updates.
+  std::set<BrowserTitlebar*> titlebars_;
+
+  friend struct DefaultSingletonTraits<GConfTitlebarListener>;
+  DISALLOW_COPY_AND_ASSIGN(GConfTitlebarListener);
+};
+
+#endif  // CHROME_BROWSER_GTK_GCONF_TITLEBAR_LISTENER_H_