Replace StatefulBaseRenderer inheritance with CanvasState member

Incrementally disentangles DisplayListRenderer and OpenGLRenderer.
Introduces abstract CanvasStateClient class to share three functions
between the two.

Design doc at https://docs.google.com/a/google.com/document/d/1PY1JF7AfPEF2UOUAnETS5j_4_tnJShTAMExvpCJfP8o/edit?usp=sharing.

BUG:15672762
R=djsollen@google.com,ccraik@google.com,jreck@google.com

Change-Id: Ic9fdffe18808e7d921ad06d01ea1ca25b2ad6f23