Clean up unused PreviewSeekBarPreferenceFragment

Usage is removed in Change: I5d8027628dcf06d99274a6a7a781218d146519eb

And we can clean up its subclasses and resources also.

Bug: 234570979
Test: m Settings
Change-Id: I4a24a34e814401749894a85375a05691b537f5a3

src/com/android/settings/accessibility/FontSizeData.java

@@ -16,8 +16,6 @@
 
 package com.android.settings.accessibility;
 
-import static com.android.settings.display.ToggleFontSizePreferenceFragment.fontSizeValueToIndex;
-
 import android.content.ContentResolver;
 import android.content.Context;
 import android.content.res.Resources;
@@ -55,4 +53,20 @@ final class FontSizeData extends PreviewSizeData<Float> {
         Settings.System.putFloat(resolver, Settings.System.FONT_SCALE,
                 getValues().get(currentProgress));
     }
+
+    /**
+     * Utility function that returns the index in a string array with which the represented value is
+     * the closest to a given float value.
+     */
+    private static int fontSizeValueToIndex(float val, String[] indices) {
+        float lastVal = Float.parseFloat(indices[0]);
+        for (int i = 1; i < indices.length; i++) {
+            float thisVal = Float.parseFloat(indices[i]);
+            if (val < (lastVal + (thisVal - lastVal) * .5f)) {
+                return i - 1;
+            }
+            lastVal = thisVal;
+        }
+        return indices.length - 1;
+    }
 }