ui/platform_window: Introduce PlatformWindow for windowing primitives.

ui/platform_window/platform_window_export.h

Index: ui/platform_window/platform_window_export.h
diff --git a/ui/platform_window/platform_window_export.h b/ui/platform_window/platform_window_export.h
new file mode 100644
index 0000000000000000000000000000000000000000..45f434a489f2ad2575aca01fd4b107719263810f
--- /dev/null
+++ b/ui/platform_window/platform_window_export.h
@@ -0,0 +1,29 @@
+// Copyright 2014 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_PLATFORM_WINDOW_PLATFORM_WINDOW_EXPORT_H_
+#define UI_PLATFORM_WINDOW_PLATFORM_WINDOW_EXPORT_H_
+
+#if defined(COMPONENT_BUILD)
+#if defined(WIN32)
+
+#if defined(PLATFORM_WINDOW_IMPLEMENTATION)
+#define PLATFORM_WINDOW_EXPORT __declspec(dllexport)
+#else
+#define PLATFORM_WINDOW_EXPORT __declspec(dllimport)
+#endif  // defined(PLATFORM_WINDOW_IMPLEMENTATION)
+
+#else  // defined(WIN32)
+#if defined(PLATFORM_WINDOW_IMPLEMENTATION)
+#define PLATFORM_WINDOW_EXPORT __attribute__((visibility("default")))
+#else
+#define PLATFORM_WINDOW_EXPORT
+#endif
+#endif
+
+#else  // defined(COMPONENT_BUILD)
+#define PLATFORM_WINDOW_EXPORT
+#endif
+
+#endif  // UI_PLATFORM_WINDOW_PLATFORM_WINDOW_EXPORT_H_