AW: add copyright headers to XML styles

No change to logic.

This only adds copyright headers to existing XML files. These files were
committed without copyright headers, but there's no reason they should
not have them.

Fixed: 1023573
Test: N/A
Change-Id: I7af8539a877784b8205ff56ce3ccfc5bc0c7a9e3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1910860
Auto-Submit: Nate Fischer <ntfschr@chromium.org>
Commit-Queue: Richard Coles <torne@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714648}

android_webview/apk/java/res_devui/values-night/styles.xml

 <?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright 2019 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.
+-->
+
 <resources>
     <style name="Theme.DevUi.DayNight" parent="@android:style/Theme.Material" />
 </resources>
\ No newline at end of file

android_webview/apk/java/res_devui/values/styles.xml

 <?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright 2019 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.
+-->
+
 <resources>
     <style name="Theme.DevUi.DayNight" parent="@android:style/Theme.Material.Light.DarkActionBar" />
 </resources>
\ No newline at end of file