Mandoline: Merge Surfaces and Views apps

Mandoline: Merge Surfaces and Views apps

Currently, the scroll position of the embedder can fall out
of sync with the position of an OOPIF's content on screen.

This CL moves towards resolving this issue.

See https://docs.google.com/document/d/13ElYs_X_UvZYXOltafyExRs7N3WwtQMBVc1eDLY2dTU/edit

The eventual goal is make a mojo::View a cc::Surface or at
least a SurfaceClient of some sort such that when the
compositor thread moves around some surfaces,
they also shift over the position of the views.

This CL merges surfaces, views and GL into one thread.
TopLevelDisplayClient has a DirectOutputSurface that uses
the SurfacesContextProvider as its ContextProvider. This
means it talks to the GL driver directly rather than going
through shared memory to hop to another thread first.

BUG=492389

Review URL: https://codereview.chromium.org/1245683004

Cr-Commit-Position: refs/heads/master@{#344296}