make setHinting(HINTING_ON) kNormal_Hinting

Previously, the default hinting mode for a freshly-constructed Paint
object is equivalent to Skia's kNormal_Hinting mode, in which font
hints are respected if available. Calling
Paint.setHinting(HINTING_ON), however, is equivalent to setting
Skia's kSlight_Hinting mode, in which font hints are ignored in
favour of freetype-generated autohints.

This discrepancy is bad for a variety of reasons:
- Once Paint.setHinting() has been called, it is impossible to return
  to the default hinting level.
- Calling paint.setHinting(otherPaint.getHinting()) can result in
  paint having a different hinting level than otherPaint.
- Paint.setHinting(HINTING_ON) actually results in font hints being
  ignored, which is perhaps the opposite of the intended behaviour.

This commit resolves these discrepancies by making HINTING_ON
correspond to Skia's kNormal_Hinting setting.

Change-Id: Iefb8e051ef53bea783e6f3be37748985ec397bc5
Bug: 9466164
1 file changed