Ensure a11y ids for LabeledSeekBar are in bounds

Bug: 64124736
Test: I just played with it with TalkBack on. The crash
was difficult to reproduce before, and I can't make it
fail now. I believe I got it.

Change-Id: I17ffe8d83e21e716d1c0cadea52afcf09bff6e97

src/com/android/settings/widget/LabeledSeekBar.java

@@ -201,6 +201,7 @@ public class LabeledSeekBar extends SeekBar {
             int posBase = Math.max(0,
                     ((int) x - LabeledSeekBar.this.getPaddingStart()) / getHalfVirtualViewWidth());
             posBase = (posBase + 1) / 2;
+            posBase = Math.min(posBase, LabeledSeekBar.this.getMax());
             return mIsLayoutRtl ? LabeledSeekBar.this.getMax() - posBase : posBase;
         }