Make DisplayListRenderer inherit from Canvas, merge JNI

Incrementally unify the upper layers for Skia and HWUI.
Remove redundant code from GLES20Canvas.java; instead
use inherited mNativeCanvasWrapper and superclass method
definitions.

Moves some unrelated SkPaint utility functions from Renderer
to new utils/PaintUtils.

bug: 15672762
Change-Id: I4ddd4214b8e9eeb95289d054ef423f2542bb5fa5
16 files changed