Implement temporary upper case hint icon

This change partially implements the requested feature. The following
are not supported yet.
- Non-letter key handling on automatic temporary upper case layout.
- Non-letter key handling on shift chording in caps lock layout.
- Hint icons for manual temporary upper case layout are not final ones.

Bug: 3193390

Change-Id: I636da99d1be05b1337935d87c6f4d140661e1cc8
diff --git a/java/res/values/attrs.xml b/java/res/values/attrs.xml
index 72e3f0d..815c7fd 100644
--- a/java/res/values/attrs.xml
+++ b/java/res/values/attrs.xml
@@ -106,12 +106,15 @@
         <attr name="keyOutputText" format="string" />
         <!-- The label to display on the key. -->
         <attr name="keyLabel" format="string" />
-        <!-- The label to display on the key when keyboard is in temporary shift mode. -->
-        <attr name="temporaryShiftKeyLabel" format="string" />
+        <!-- The unicode that this key generates in manual temporary upper case mode. -->
+        <attr name="manualTemporaryUpperCaseCode" format="integer" />
         <!-- The icon to display on the key instead of the label. -->
         <attr name="keyIcon" format="reference" />
         <!-- The hint icon to display on the key in conjunction with the label -->
         <attr name="keyHintIcon" format="reference" />
+        <!-- The hint icon to display on the key when keyboard is in manual temporary upper case
+             mode. -->
+        <attr name="manualTemporaryUpperCaseHintIcon" format="reference" />
     </declare-styleable>
 
     <declare-styleable name="BaseKeyboard_Row">