Unbundle Keyboard.java to BaseKeyboard.java

Change-Id: I8b310c2c0cae1a151e53c22001c586697346982c

java/res/xml/kbd_popup_template.xml

@@ -18,10 +18,10 @@
 */
 -->
 
-<Keyboard xmlns:android="http://schemas.android.com/apk/res/android"
-    android:keyWidth="10%p"
-    android:horizontalGap="0px"
-    android:verticalGap="0px"
-    android:keyHeight="@dimen/key_height"
+<Keyboard xmlns:latin="http://schemas.android.com/apk/res/com.android.inputmethod.latin"
+    latin:keyWidth="10%p"
+    latin:horizontalGap="0px"
+    latin:verticalGap="0px"
+    latin:keyHeight="@dimen/key_height"
     >
 </Keyboard>