Enable -Wextra-tokens on win clang.

Enable -Wextra-tokens on win clang.

This warns on code of the form:
#endif RANDOM_TEXT
MIDL generated code tends to emit code in this pattern, so suppress
this warning when compiling MIDL generated files.

BUG=504663
R=thakis@chromium.org
TBR=dtseng, robertshield, weitaosu

Committed: https://chromium.googlesource.com/chromium/src/+/be8d6f52672bf61324b2ac988ef7776ade9d1628

[dcheng, 2015-07-11 01:37:46]

dcheng@chromium.org changed reviewers:
+ thakis@chromium.org

[Nico, 2015-07-11 03:32:50]

lgtm, nice :-)

Bonus for filing a microsoft connect bug so that midl hopefully eventually stops
doing this.

[dcheng, 2015-07-11 04:27:18]

dcheng@chromium.org changed reviewers:
+ dtseng@chromium.org, robertshield@chromium.org, weitaosu@chromium.org

[commit-bot: I haz the power, 2015-07-11 05:18:50]

Patchset 2 (id:??) landed as
https://crrev.com/be8d6f52672bf61324b2ac988ef7776ade9d1628
Cr-Commit-Position: refs/heads/master@{#338435}

[dcheng, 2015-07-11 05:25:38]

Committed patchset #2 (id:20001) manually as
be8d6f52672bf61324b2ac988ef7776ade9d1628 (presubmit successful).