aura: Make 'ui' buildable without gtk.

ui/base/clipboard/clipboard.h

 // Copyright (c) 2011 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_CLIPBOARD_CLIPBOARD_H_
 #define UI_BASE_CLIPBOARD_CLIPBOARD_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 237 matching lines @@
 
   // Return the window that should be the clipboard owner, creating it
   // if neccessary.  Marked const for lazily initialization by const methods.
   HWND GetClipboardWindow() const;
 
   // Mark this as mutable so const methods can still do lazy initialization.
   mutable HWND clipboard_owner_;
 
   // True if we can create a window.
   bool create_window_;
-#elif !defined(OS_MACOSX)
+#elif defined(TOOLKIT_USES_GTK)
   // The public API is via WriteObjects() which dispatches to multiple
   // Write*() calls, but on GTK we must write all the clipboard types
   // in a single GTK call.  To support this we store the current set
   // of data we intend to put on the clipboard on clipboard_data_ as
   // WriteObjects is running, and then at the end call SetGtkClipboard
   // which replaces whatever is on the system clipboard with the
   // contents of clipboard_data_.
 
  public:
   typedef std::map<FormatType, std::pair<char*, size_t> > TargetMap;
@@ skipping 16 matching lines @@
   static const char kMimeTypeText[];
   static const char kMimeTypeHTML[];
   static const char kMimeTypePNG[];
 
   DISALLOW_COPY_AND_ASSIGN(Clipboard);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_CLIPBOARD_CLIPBOARD_H_