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