Fix bug #5199577 TextView with android:password="true" is showing the "dots" on the left even if the password chars are RTL

- force TextView to LOCALE text heuristic when in "password" mode
- remove TEXT_LAYOUT_DIRECTION_UNKNOWN_DO_NOT_USE
- LocaleUtils.getLayoutDirectionFromLocale() returns "LTR" is locale is NULL or ROOT

Change-Id: I182c46aaf2d73c8b18967fffa230bfabec91ed06
diff --git a/core/java/android/text/TextDirectionHeuristics.java b/core/java/android/text/TextDirectionHeuristics.java
index 6debc6b..18b4040 100644
--- a/core/java/android/text/TextDirectionHeuristics.java
+++ b/core/java/android/text/TextDirectionHeuristics.java
@@ -17,6 +17,10 @@
 package android.text;
 
 
+import java.util.Locale;
+
+import android.util.LocaleUtil;
+
 /**
  * Some objects that implement TextDirectionHeuristic.
  * @hide
@@ -75,6 +79,11 @@
     public static final TextDirectionHeuristic CHARCOUNT_RTL =
         new TextDirectionHeuristicInternal(CharCount.INSTANCE_DEFAULT, true);
 
+    /**
+     * Force the paragraph direction to the Locale direction. Falls back to left to right.
+     */
+    public static final TextDirectionHeuristic LOCALE = TextDirectionHeuristicLocale.INSTANCE;
+
     private static enum TriState {
         TRUE, FALSE, UNKNOWN;
     }
@@ -300,4 +309,23 @@
         public static final float DEFAULT_THRESHOLD = 0.6f;
         public static final CharCount INSTANCE_DEFAULT = new CharCount(DEFAULT_THRESHOLD);
     }
+
+    /**
+     * Algorithm that uses the Locale direction to force the direction of a paragraph.
+     */
+    public static class TextDirectionHeuristicLocale extends TextDirectionHeuristicImpl {
+
+        public TextDirectionHeuristicLocale() {
+            super(null);
+        }
+
+        @Override
+        protected boolean defaultIsRtl() {
+            final int dir = LocaleUtil.getLayoutDirectionFromLocale(java.util.Locale.getDefault());
+            return (dir == LocaleUtil.TEXT_LAYOUT_DIRECTION_RTL_DO_NOT_USE);
+        }
+
+        public static final TextDirectionHeuristicLocale INSTANCE =
+                new TextDirectionHeuristicLocale();
+    }
 }