gpu, cmaa: Stringify shaders

BUG=535198
TEST=Run a WebGL app with Chrome started with "--enable-cmaa-shaders"
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_optional_gpu_tests_rel;tryserver.chromium.mac:mac_optional_gpu_tests_rel;tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2091643003
Cr-Commit-Position: refs/heads/master@{#401886}
1 file changed