Tune left and right padding of popup mini keyboard

This change also fix popup window display position calculation.

Bug: 3029284
Change-Id: I28bf3e4deb46a428dc8422a3a165183e00608604
diff --git a/java/res/layout/keyboard_popup.xml b/java/res/layout/keyboard_popup.xml
index 9a52e2c..27388e0 100644
--- a/java/res/layout/keyboard_popup.xml
+++ b/java/res/layout/keyboard_popup.xml
@@ -23,6 +23,8 @@
         android:layout_height="wrap_content"
         android:orientation="horizontal"
         android:background="@drawable/keyboard_popup_panel_background"
+        android:paddingLeft="16dip"
+        android:paddingRight="16dip"
         >
     <com.android.inputmethod.latin.LatinKeyboardBaseView
             xmlns:latin="http://schemas.android.com/apk/res/com.android.inputmethod.latin"