Use functional key background for action key with label

This CL also adds label_search_key string resources for consistency.

Bug: 15135033
Change-Id: I81cae243e83a590ef56fe758a43c7184fc4159aa
diff --git a/java/res/values/strings-action-keys.xml b/java/res/values/strings-action-keys.xml
index 7003784..96b2e7d 100644
--- a/java/res/values/strings-action-keys.xml
+++ b/java/res/values/strings-action-keys.xml
@@ -29,6 +29,8 @@
     <string name="label_done_key">Done</string>
     <!-- Label for soft enter key when it performs SEND action.  Must be short to fit on key. 5 chars or less is preferable.  [CHAR LIMIT=7] -->
     <string name="label_send_key">Send</string>
+    <!-- Label for soft enter key when it performs SEARCH action.  Must be short to fit on key. 5 chars or less is preferable.  [CHAR LIMIT=7] -->
+    <string name="label_search_key">Search</string>
     <!-- Label for "Pause" key of phone number keyboard.  Must be short to fit on key. 5 chars or less is preferable.  [CHAR LIMIT=7] -->
     <string name="label_pause_key">Pause</string>
     <!-- Label for "Wait" key of phone number keyboard.  Must be short to fit on key. 5 chars or less is preferable.  [CHAR LIMIT=7]-->