When using ninja and clang, make sure diagnostics are colored.
When using ninja and clang, make sure diagnostics are colored.

BUG=none
LOG=N

Review URL: https://codereview.chromium.org/969653004

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#26976}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh