Index out of range problem in TextLine.

Recent refactoring for bidi introduced an index shift in the getOffsetBeforeAfter
method. This problem appears for multi-line text input only, when the text line
mStart index is not 0.

As a result, moving the cursor using the trackball in a multi-line EditText crashes.

Change-Id: I1f121f0f9272ef7d338399f369ba6d77e1ca71c5

core/java/android/text/TextLine.java

@@ -54,7 +54,7 @@ class TextLine {
     private char[] mChars;
     private boolean mCharsValid;
     private Spanned mSpanned;
-    private TextPaint mWorkPaint = new TextPaint();
+    private final TextPaint mWorkPaint = new TextPaint();
 
     private static TextLine[] cached = new TextLine[3];
 
@@ -658,7 +658,7 @@ class TextLine {
                     flags, offset, cursorOpt);
         } else {
             return wp.getTextRunCursor(mText, mStart + spanStart,
-                    mStart + spanLimit, flags, mStart + offset, cursorOpt);
+                    mStart + spanLimit, flags, mStart + offset, cursorOpt) - mStart;
         }
     }