Remove bundled gsettings header now that we're using Ubuntu Precise.

build/linux/gsettings.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 BUILD_LINUX_GSETTINGS_H_
-#define BUILD_LINUX_GSETTINGS_H_
-
-#include <gio/gio.h>
-
-// The GSettings API was not part of GIO until GIO version 2.26,
-// while Ubuntu 10.04 Lucid ships with version 2.24.
-//
-// To allow compiling on Lucid those forward declarations are provided.
-//
-// If compiling with GIO version 2.26, these won't conflict,
-// because they're identical to the types defined.
-//
-// TODO(phajdan.jr): This will no longer be needed after switch to Precise,
-// see http://crbug.com/158577 .
-struct _GSettings;
-typedef struct _GSettings GSettings;
-GSettings* g_settings_new(const gchar* schema);
-GSettings* g_settings_get_child(GSettings* settings, const gchar* name);
-gboolean g_settings_get_boolean(GSettings* settings, const gchar* key);
-gchar* g_settings_get_string(GSettings* settings, const gchar* key);
-gint g_settings_get_int(GSettings* settings, const gchar* key);
-gchar** g_settings_get_strv(GSettings* settings, const gchar* key);
-const gchar* const* g_settings_list_schemas();
-
-#endif  // BUILD_LINUX_GSETTINGS_H_