Use correct config variable in command buffer gl context

Use correct config variable in command buffer gl context.
Before, the fConfig was errorneously used to initialize the
local variable. eglChooseConfig would update the local variable
and the fConfig member variable would never be updated.

Also add error checks to all initialization function calls.

BUG=skia:

Review URL: https://codereview.chromium.org/1505233002
1 file changed