Fix some memory leaks.

ui/base/x/x11_util.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_X_X11_UTIL_H_
 #define UI_BASE_X_X11_UTIL_H_
 #pragma once
 
 // This file declares utility functions for X11 (Linux only).
 //
@@ skipping 237 matching lines @@
 // received.
 UI_EXPORT void UpdateButtonMap();
 
 // Initializes a XEvent that holds XKeyEvent for testing. Note that ui::EF_
 // flags should be passed as |flags|, not the native ones in <X11/X.h>.
 UI_EXPORT void InitXKeyEventForTesting(EventType type,
                                        KeyboardCode key_code,
                                        int flags,
                                        XEvent* event);
 
+// Keeps track of a string returned by an X function (e.g. XGetAtomName) and
+// makes sure it's XFree'd.
+class UI_EXPORT XScopedString {
+ public:
+  explicit XScopedString(char* str) : string_(str) { }
+  ~XScopedString();
+
+  const char* string() const { return string_; }
+
+ private:
+  char* string_;
+
+  DISALLOW_COPY_AND_ASSIGN(XScopedString);
+};
+
 }  // namespace ui
 
 #endif  // UI_BASE_X_X11_UTIL_H_