gpu: Move native memory buffer configuration into //gpu

This moves the code for getting the supported native memory buffer
configurations out of //content into //gpu. This allows this code
to be used by mus too.

BUG=643746
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2551743002
Cr-Commit-Position: refs/heads/master@{#437182}
17 files changed