The context parameter of Shader::resolveCompile method causes a bad
impact that many methods in Shader, Program etc. have to have a same
context parameter. By removing it, these methods can be decoupled
from Context.

BUG=chromium:849576

Change-Id: Ia5545ee9dce45794550f6086bc0e6c4707e1276e
Reviewed-on: https://chromium-review.googlesource.com/1172202
Commit-Queue: Jie A Chen <jie.a.chen@intel.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>