Add command_buffer_gles2
This is a very simple library that exposes some egl-like functions that
can be used by skia to use the command buffer as a backend for their
tests
Committed: https://crrev.com/
604b615373e4e9f873db37cef9c6416176fc35f3
Cr-Commit-Position: refs/heads/master@{#346251}
Committed: https://crrev.com/
efa3a446183fbbff2034a03989f12543d0713e39
Cr-Commit-Position: refs/heads/master@{#346840}
Committed: https://crrev.com/
d65c55dac3f47e9a237579eb6f5fe31e19ca4704
Cr-Commit-Position: refs/heads/master@{#347013}
Review URL: https://codereview.chromium.org/
1220883008
Cr-Commit-Position: refs/heads/master@{#347103}