Convert Ozone cast to directly create GLSurfaces.

The Ozone cast platform now directly creates an appropriate GLSurface
instead of creating a SurfaceOzoneEGL. Remove the SurfaceOzoneEGL
subclass and add a new GLSurface subclass.

BUG=611142

Review-Url: https://codereview.chromium.org/2179163003
Cr-Commit-Position: refs/heads/master@{#408133}
8 files changed