Move gtk_settings_get_default() call to the UI thread.

base/mime_util.h

 // 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.
 
 #ifndef BASE_MIME_UTIL_H_
 #define BASE_MIME_UTIL_H_
 
 #include <string>
 
 class FilePath;
 
 namespace mime_util {
 
 // Gets the mime type for a file based on its filename. The file path does not
 // have to exist. Please note because it doesn't touch the disk, this does not
 // work for directories.
 // If the mime type is unknown, this will return application/octet-stream.
 std::string GetFileMimeType(const FilePath& filepath);
 
 // Get the mime type for a byte vector.
 std::string GetDataMimeType(const std::string& data);
 
+#if defined(OS_LINUX)
+// This detects the current GTK theme by calling gtk_settings_get_default().
+// It should only be executed on the UI thread and must be called before
+// GetMimeIcon().
+void DetectGtkTheme();
+#endif
+
 // Gets the file name for an icon given the mime type and icon pixel size.
 // Where an icon is a square image of |size| x |size|.
 // This will try to find the closest matching icon. If that's not available,
 // then a generic icon, and finally an empty FilePath if all else fails.
 FilePath GetMimeIcon(const std::string& mime_type, size_t size);
 
 }  // namespace mime_util
 
 #endif  // BASE_MIME_UTIL_H_