Adds remaining missing overrides and nullptr usages, missed due to
an extreme failure in tool usage.
Change-Id: I56abd72975a3999ad13330003c348db40f59aebf
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