Remove oak windows and its flags.

ui/oak/oak_export.h

Index: ui/oak/oak_export.h
diff --git a/ui/oak/oak_export.h b/ui/oak/oak_export.h
deleted file mode 100644
index 726366c6a700da6bf7d52a1340ed2b33ae0458a0..0000000000000000000000000000000000000000
--- a/ui/oak/oak_export.h
+++ /dev/null
@@ -1,32 +0,0 @@
-// 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_OAK_OAK_EXPORT_H_
-#define UI_OAK_OAK_EXPORT_H_
-
-// Defines AURA_EXPORT so that functionality implemented by the aura module
-// can be exported to consumers.
-
-#if defined(COMPONENT_BUILD)
-#if defined(WIN32)
-
-#if defined(OAK_IMPLEMENTATION)
-#define OAK_EXPORT __declspec(dllexport)
-#else
-#define OAK_EXPORT __declspec(dllimport)
-#endif  // defined(OAK_IMPLEMENTATION)
-
-#else  // defined(WIN32)
-#if defined(OAK_IMPLEMENTATION)
-#define OAK_EXPORT __attribute__((visibility("default")))
-#else
-#define OAK_EXPORT
-#endif
-#endif
-
-#else  // defined(COMPONENT_BUILD)
-#define OAK_EXPORT
-#endif
-
-#endif  // UI_OAK_OAK_EXPORT_H_