Add wallpaper support to theme bundles

Show wallpaper preview if available, show a checkbox to keep the
current wallpaper and apply the theme's wallpaper if needed.

Bug: 120559294

Change-Id: I229ab6e3372ace8218356d965e8d38f074e95061
diff --git a/res/values/strings.xml b/res/values/strings.xml
index e491c39..e451795 100755
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -38,6 +38,10 @@
         [CHAR LIMIT=20] -->
     <string name="apply_theme_btn">Apply</string>
 
+    <!-- Label for a checkbox to allow the user to use their currently set wallpaper instead of
+        the one bundled with selected Theme [CHAR LIMIT=35]-->
+    <string name="keep_my_wallpaper">Keep current wallpaper</string>
+
     <!-- Label for a button that allows the user to apply the currently selected customization option.
         [CHAR LIMIT=20] -->
     <string name="apply_btn">Apply</string>
@@ -81,4 +85,8 @@
 
     <!-- Message shown when a theme has been applied successfully in the system [CHAR LIMIT=NONE] -->
     <string name="applied_theme_msg">Style applied</string>
+
+    <!-- Message shown when a theme couldn't be applied in the system because of an error
+        [CHAR LIMIT=NONE] -->
+    <string name="apply_theme_error_msg">There was a problem applying the style</string>
 </resources>