Add a windows_xfa_clang trybot and enable clang_use_chrome_plugins

Add a windows_xfa_clang trybot and enable clang_use_chrome_plugins

Add a windows_xfa_clang trybot to capture some errors before committing
the code.

After we have removed all warnings generated by clang_use_chrome_plugins,
enable clang_use_chrome_plugins, which by default is enabled when clang
is used.

BUG=chromium:619726, pdfium:469
Committed: https://chromium.googlesource.com/chromium/tools/build/+/3bb22ab158e5ff15dbfa296d7940a67db83f9c45

[Wei Li, 2016-06-20 22:14:40]

weili@chromium.org changed reviewers:
+ dpranke@chromium.org, ochang@chromium.org

[Wei Li, 2016-06-20 22:14:41]

pls review, thanks

[Oliver Chang, 2016-06-20 22:18:29]

lgtm

[Wei Li, 2016-06-21 15:14:22]

The CQ bit was checked by weili@chromium.org

[commit-bot: I haz the power, 2016-06-21 15:14:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2085733002/1

[commit-bot: I haz the power, 2016-06-21 15:14:34]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-06-21 15:14:35]

No L-G-T-M from a valid reviewer yet. 
CQ run can only be started by full committers or once the patch has
received an L-G-T-M from a full committer.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
Committers are members of the group "project-infra-committers".
Note that this has nothing to do with OWNERS files.

[Dirk Pranke, 2016-06-21 16:19:39]

lgtm

[Wei Li, 2016-06-21 16:20:21]

The CQ bit was checked by weili@chromium.org

[commit-bot: I haz the power, 2016-06-21 16:20:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2085733002/1

[commit-bot: I haz the power, 2016-06-21 16:23:16]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-06-21 16:23:17]

Try jobs failed on following builders:
  Build Presubmit on tryserver.infra (JOB_FAILED,
https://build.chromium.org/p/tryserver.infra/builders/Build%20Presubmit/build...)

[Wei Li, 2016-06-21 17:27:10]

The CQ bit was checked by weili@chromium.org

[Wei Li, 2016-06-21 17:27:10]

The patchset sent to the CQ was uploaded after l-g-t-m from ochang@chromium.org,
dpranke@chromium.org
Link to the patchset: https://codereview.chromium.org/2085733002/#ps20001
(title: "rebase")

[commit-bot: I haz the power, 2016-06-21 17:27:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2085733002/20001

[commit-bot: I haz the power, 2016-06-21 17:31:54]

Description was changed from

==========
Add a windows_xfa_clang trybot and enable clang_use_chrome_plugins

Add a windows_xfa_clang trybot to capture some errors before committing
the code.

After we have removed all warnings generated by clang_use_chrome_plugins,
enable clang_use_chrome_plugins, which by default is enabled when clang
is used.

BUG=chromium:619726,pdfium:469
==========

to

==========
Add a windows_xfa_clang trybot and enable clang_use_chrome_plugins

Add a windows_xfa_clang trybot to capture some errors before committing
the code.

After we have removed all warnings generated by clang_use_chrome_plugins,
enable clang_use_chrome_plugins, which by default is enabled when clang
is used.

BUG=chromium:619726,pdfium:469

Committed:
https://chromium.googlesource.com/chromium/tools/build/+/3bb22ab158e5ff15dbfa...
==========

[commit-bot: I haz the power, 2016-06-21 17:31:55]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/tools/build/+/3bb22ab158e5ff15dbfa...