Extracted the HTML format logic to the HtmlFormatter

[ivannarino]

This allows to format an HTML string without having to use an HtmlTextView in the layout.

Also this allows to customize the html before passing it to the TextView, for example one could change all BulletSpans with its own implementation.

Spanned formattedHtml = HtmlFormatter.formatHtml(new HtmlFormatterBuilder().setHtml("<h2>Hello wold</h2><ul><li>cats</li><li>dogs</li></ul><img src=\"cat_pic\"/>").setImageGetter(new HtmlResImageGetter(htmlTextView.getContext())));
SpannableStringBuilder textSpanBuilder = new SpannableStringBuilder(formattedHtml);
final BulletSpan[] bulletSpans = textSpanBuilder.getSpans(0, text.length(), BulletSpan.class);
for (final BulletSpan bulletSpan : bulletSpans) {
  int start = text.getSpanStart(bulletSpan);
  int end = text.getSpanEnd(bulletSpan);
  textSpanBuilder.removeSpan(bulletSpan);
  textSpanBuilder.setSpan(
    new FixedBulletSpan(bulletSpan.getGapWidth()),
    start,
    end,
    Spanned.SPAN_INCLUSIVE_EXCLUSIVE
  );
}

HtmlFormatterBuilder parameter uses the builder pattern.

Removed unused HtmlTagHandler#mTextPaint
Replace HtmlResImageGetter#container TextView with Context