Implement --ozone-platform flag to select OzonePlatform implementation at runtime

ui/ozone/ozone_platform_list.h

Index: ui/ozone/ozone_platform_list.h
diff --git a/ui/ozone/ozone_platform_list.h b/ui/ozone/ozone_platform_list.h
new file mode 100644
index 0000000000000000000000000000000000000000..bac8d9664fa1370fd7b81fc395194a75e14a7eb1
--- /dev/null
+++ b/ui/ozone/ozone_platform_list.h
@@ -0,0 +1,25 @@
+// Copyright (c) 2013 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_OZONE_OZONE_PLATFORM_LIST_H_
+#define UI_OZONE_OZONE_PLATFORM_LIST_H_
+
+namespace ui {
+
+class OzonePlatform;
+
+typedef OzonePlatform* (*OzonePlatformConstructor)();
+
+struct OzonePlatformListEntry {
+  const char* name;
+  OzonePlatformConstructor constructor;
+};
+
+extern const OzonePlatformListEntry kOzonePlatforms[];
+
+extern const int kOzonePlatformCount;
+
+}  // namespace ui
+
+#endif  // UI_OZONE_OZONE_PLATFORM_LIST_H_