This does way more than a single CL should do, sorry.
- Fixed a bunch of logging/error reporting during loads.
- Made it possible for --package-root to be absolute.
- Fixed (hypothetically) parts of iOS build to be clang-plugin-compliant.
- Made all tests pass in sky_shell
- Removed a bunch of layout_tests including windows support.
I'll remove all the mojo test harness stuff in a follow-up patch.
R=abarth@chromium.org, abarth@google.com
Review URL: https://codereview.chromium.org/1215953006.
63cefd8bc1