Make Clang's update.py use the Win toolchain under depot_tools if available

Make Clang's update.py use the Win toolchain under depot_tools if available

Clang should be built with the same toolchain used to build Chromium,
which is typically the one in depot_tools/win_toolchain.

BUG=82385
R=scottmg@chromium.org

Committed: https://chromium.googlesource.com/chromium/src/+/28fb41c40e75fa0896058996d7cde447902b3ed2

[hans, 2014-09-22 18:57:19]

hans@chromium.org changed reviewers:
+ rnk@chromium.org, scottmg@chromium.org, thakis@chromium.org

[hans, 2014-09-22 18:57:19]

Please take a look.


One annoying thing is that builds that have successfully used the system
toolchain before (e.g. all the buildbots), won't start using the toolchain in
depot_tools, because CMake caches its compiler choice. I don't know if it's
worth doing something to nuke that cache for a change like this.

[scottmg, 2014-09-22 18:59:48]

https://codereview.chromium.org/587383003/diff/1/tools/clang/scripts/update.py
File tools/clang/scripts/update.py (right):

https://codereview.chromium.org/587383003/diff/1/tools/clang/scripts/update.p...
tools/clang/scripts/update.py:144: json_data_file = os.path.join(CHROMIUM_DIR,
'build', 'win_toolchain.json')
could you import vs_toolchain and call SetEnvironmentAndGetRuntimeDllDirs
instead?

[hans, 2014-09-22 19:52:39]

https://codereview.chromium.org/587383003/diff/1/tools/clang/scripts/update.py
File tools/clang/scripts/update.py (right):

https://codereview.chromium.org/587383003/diff/1/tools/clang/scripts/update.p...
tools/clang/scripts/update.py:144: json_data_file = os.path.join(CHROMIUM_DIR,
'build', 'win_toolchain.json')
On 2014/09/22 18:59:48, scottmg wrote:
> could you import vs_toolchain and call SetEnvironmentAndGetRuntimeDllDirs
> instead?

Done.

[scottmg, 2014-09-22 19:54:51]

lgtm if it works!

https://codereview.chromium.org/587383003/diff/20001/tools/clang/scripts/upda...
File tools/clang/scripts/update.py (right):

https://codereview.chromium.org/587383003/diff/20001/tools/clang/scripts/upda...
tools/clang/scripts/update.py:9: import json
unneeded now

[hans, 2014-09-22 23:01:04]

The CQ bit was checked by hans@chromium.org

[commit-bot: I haz the power, 2014-09-22 23:01:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/587383003/40001

[commit-bot: I haz the power, 2014-09-22 23:17:01]

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

[commit-bot: I haz the power, 2014-09-22 23:17:02]

Try jobs failed on following builders:
  mac_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/mac_gpu/builds/59236)

[commit-bot: I haz the power, 2014-09-22 23:28:32]

Patchset 3 (id:??) landed as
https://crrev.com/28fb41c40e75fa0896058996d7cde447902b3ed2
Cr-Commit-Position: refs/heads/master@{#296090}

[hans, 2014-09-22 23:28:37]

Committed patchset #3 (id:40001) manually as 28fb41c (presubmit successful).