Update Chromium docs on using clang

Update Chromium docs on using clang

- Goma should work with clang on Windows
- Mention LLD
- Rearrange the build instructions, people probably just want to see the
  GYP_DEFINES and args.gn first

R=thakis@chromium.org,hans@chromium.org

Committed: https://crrev.com/c052ba3783ce522a860c9fe981dff01f339fbdc1
Cr-Commit-Position: refs/heads/master@{#387089}

[Nico, 2016-04-13 00:50:14]

lgtm!

https://codereview.chromium.org/1881283002/diff/1/docs/clang.md
File docs/clang.md (right):

https://codereview.chromium.org/1881283002/diff/1/docs/clang.md#newcode17
docs/clang.md:17: ### Ninja
(we can probably drop this heading too; all platforms are on ninja by now)

https://codereview.chromium.org/1881283002/diff/1/docs/clang.md#newcode91
docs/clang.md:91: 
mention somewhere here that update.py only needs to be run once and autoupdates
after that. maybe just paste the "(Only needs to be run once per checkout, and
clang will be …" bit here

[Reid Kleckner, 2016-04-13 18:11:47]

https://codereview.chromium.org/1881283002/diff/1/docs/clang.md
File docs/clang.md (right):

https://codereview.chromium.org/1881283002/diff/1/docs/clang.md#newcode91
docs/clang.md:91: 
On 2016/04/13 00:50:14, Nico wrote:
> mention somewhere here that update.py only needs to be run once and
autoupdates
> after that. maybe just paste the "(Only needs to be run once per checkout, and
> clang will be …" bit here

What about simplifying this to `gclient runhooks` here and above? Is that too
slow?

[Nico, 2016-04-13 18:13:58]

https://codereview.chromium.org/1881283002/diff/1/docs/clang.md
File docs/clang.md (right):

https://codereview.chromium.org/1881283002/diff/1/docs/clang.md#newcode91
docs/clang.md:91: 
On 2016/04/13 18:11:47, Reid Kleckner wrote:
> On 2016/04/13 00:50:14, Nico wrote:
> > mention somewhere here that update.py only needs to be run once and
> autoupdates
> > after that. maybe just paste the "(Only needs to be run once per checkout,
and
> > clang will be …" bit here
> 
> What about simplifying this to `gclient runhooks` here and above? Is that too
> slow?

It's not enough in a gn build, since runhooks calls update.py with --if-needed,
and that exits on Windows unless clang=1 is in GYP_DEFINES (which it isn't in gn
builds)

[Reid Kleckner, 2016-04-13 20:38:40]

The CQ bit was checked by rnk@chromium.org

[Reid Kleckner, 2016-04-13 20:38:40]

The patchset sent to the CQ was uploaded after l-g-t-m from thakis@chromium.org
Link to the patchset: https://codereview.chromium.org/1881283002/#ps20001
(title: "update")

[commit-bot: I haz the power, 2016-04-13 20:38:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1881283002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1881283002/20001

[commit-bot: I haz the power, 2016-04-13 21:13:09]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-04-13 21:14:43]

Description was changed from

==========
Update Chromium docs on using clang

- Goma should work with clang on Windows
- Mention LLD
- Rearrange the build instructions, people probably just want to see the
  GYP_DEFINES and args.gn first

R=thakis@chromium.org,hans@chromium.org
==========

to

==========
Update Chromium docs on using clang

- Goma should work with clang on Windows
- Mention LLD
- Rearrange the build instructions, people probably just want to see the
  GYP_DEFINES and args.gn first

R=thakis@chromium.org,hans@chromium.org

Committed: https://crrev.com/c052ba3783ce522a860c9fe981dff01f339fbdc1
Cr-Commit-Position: refs/heads/master@{#387089}
==========

[commit-bot: I haz the power, 2016-04-13 21:14:44]

Patchset 2 (id:??) landed as
https://crrev.com/c052ba3783ce522a860c9fe981dff01f339fbdc1
Cr-Commit-Position: refs/heads/master@{#387089}