[Ozone] Fix component build

Missing header include would result in symbols being defined locally
only.

TBR=spang@chromium.org
NOTRY=true
BUG=none

Review URL: https://codereview.chromium.org/335663002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@276744 0039d316-1c4b-4281-b951-d872f2087c98

ui/ozone/platform_selection.cc

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "ui/ozone/platform_selection.h"
+
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "ui/ozone/ozone_switches.h"