win: Set is_clang=true by default
A notification will be sent to chromium-dev if this sticks.
Some blink baselines shift due to different rounding behaviour. In the
majority of cases, this means the Windows and Mac/Linux baselines now
become identical.
This also switches win_clang bots to use MSVC as compiler, to make sure
things stay compilable with MSVC.
Known problems:
* Build times without goma are slower (but you can do goma builds with
debug info now, which are faster).
* Incremental linking of webcore.dll doesn't work (see crbug.com/717207
and crbug.com/560475)
BUG=82385,709690
Change-Id: I67421a5aee2259cf98b93d34d69a3314dbd98304
Reviewed-on: https://chromium-review.googlesource.com/588077
Commit-Queue: Hans Wennborg <hans@chromium.org>
Reviewed-by: Brett Wilson <brettw@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490494}647 files changed
