Support keyboardHeight and maxKeyboardHeight to Keyboard XML

This change introduces,
- new attribute keyboardHeight to specify default keyboard height.
- new attribute maxKeyboardHeight to specify maximum keyboard height,
  usually specified by percentage to the screen height.
- keyHeight attribute is obsoleted
- new attribute rowHeight to specify a row height, can be specifed as
  percentage of the keyboard height. And verticalGap is included to
  the row height (row height = key height + vertical gap).

Change-Id: I48a2f2661e8a91a998503a847437c1baf1de9b9c
diff --git a/java/res/values/attrs.xml b/java/res/values/attrs.xml
index 4fc5351..55c806c 100644
--- a/java/res/values/attrs.xml
+++ b/java/res/values/attrs.xml
@@ -76,10 +76,15 @@
     </declare-styleable>
 
     <declare-styleable name="Keyboard">
+        <!-- Default keyboard height -->
+        <attr name="keyboardHeight" format="dimension" />
+        <!-- Maximum keyboard height, in pixels or percentage of display height -->
+        <attr name="maxKeyboardHeight" format="dimension|fraction" />
         <!-- Default width of a key, in pixels or percentage of display width. -->
         <attr name="keyWidth" format="dimension|fraction" />
-        <!-- Default height of a key, in pixels or percentage of display width. -->
-        <attr name="keyHeight" format="dimension|fraction" />
+        <!-- Default height of a row (key height + vertical gap), in pixels or percentage of
+             keyboard height. -->
+        <attr name="rowHeight" format="dimension|fraction" />
         <!-- Default horizontal gap between keys. -->
         <attr name="horizontalGap" format="dimension|fraction" />
         <!-- Default vertical gap between rows of keys. -->