egl: Add EGL extension for front buffer auto-refresh mode

- Add an EGL extension for enabling/disabling auto-refresh mode on
  a surface that's being used for front-buffer rendering.
- Remove the temporary hack that was directly enabling/disabling
  front-buffer rendering from the EGL wrapper. From now on the driver
  will have to implement it.

Bug 24949410

Change-Id: I722577521a37f9892dbadaf504b4551fe37182ed