Layers require that drawing methods potentially
draw in more than one bitmaps.
To handle this this patch offers the following:
- move all drawing methods to use Drawable
- Drawables are now handled by GcSnapshot since
its the one handling the layers
- moved Canvas_Delegate.createCustomGraphics to
GcSnapshot which does not expose the Graphics2D
objects anymore so its draw() methods are the only
way to draw.
- handles creating layers in GcSnapshot.save() and
blitting them in restore()
Other changes:
- Clean up the create/save API in GcSnapshot
- Fixed drawing bitmaps with alpha and other
composite modes.
Change-Id: I1e230087493d044a10de71f4b6d29083e3f3bf64
d38e776a3c