Add emoji icon and code as a groundwork

The emoji switching key icon asset should be updated. The icons in
this change are just borrowed from Hangout.

Bug: 10179862
Bug: 6370846
Change-Id: Icea26d2cf2ac6a6df9beb4c98f646dbe309bdcd9
diff --git a/java/res/values/attrs.xml b/java/res/values/attrs.xml
index c318317..b8a84e3 100644
--- a/java/res/values/attrs.xml
+++ b/java/res/values/attrs.xml
@@ -217,6 +217,7 @@
         <attr name="iconLanguageSwitchKey" format="reference" />
         <attr name="iconZwnjKey" format="reference" />
         <attr name="iconZwjKey" format="reference" />
+        <attr name="iconEmojiKey" format="reference" />
     </declare-styleable>
 
     <declare-styleable name="Keyboard_Key">