Add more gn documentation

Add more gn documentation

Adds new topics on labels, overall build flow, and ninja rule generation.
Enhances toolchain documentation. Removes duplicate content from language.md
(which I want to go away -- this should be moved into the builtin help).

Committed: https://crrev.com/189c461d55de98bab1f85abcac8e54203a1b9633
Cr-Commit-Position: refs/heads/master@{#432766}

[brettw, 2016-11-16 18:52:29]

brettw@chromium.org changed reviewers:
+ dpranke@chromium.org

[brettw, 2016-11-16 20:30:16]

The CQ bit was checked by brettw@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-16 20:31:27]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-16 21:09:33]

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

[commit-bot: I haz the power, 2016-11-16 21:09:34]

Dry run: This issue passed the CQ dry run.

[Dirk Pranke, 2016-11-17 02:57:45]

lgtm.

Looks like someone likes using raw string literals :).

More seriously, if we do want to get rid of language.md and move more stuff into
the built in help -- which seems like a good idea -- we should probably spend
some time trying to figure out if we can organize the generated reference.md
better (add a more useful TOC, format things better, etc.) As it is now, it's
not super-easy to read or navigate.

[brettw, 2016-11-17 05:31:47]

The raw strings make this so much easier to write!

I'm also going to delete the cookbook which is out-of-date and geared toward the
GYP transition.

[brettw, 2016-11-17 05:31:52]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2016-11-17 05:32:43]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-17 05:39:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-17 05:41:10]

Description was changed from

==========
Add more gn documentation

Adds new topics on labels, overall build flow, and ninja rule generation.
Enhances toolchain documentation. Removes duplicate content from language.md
(which I want to go away -- this should be moved into the builtin help).
==========

to

==========
Add more gn documentation

Adds new topics on labels, overall build flow, and ninja rule generation.
Enhances toolchain documentation. Removes duplicate content from language.md
(which I want to go away -- this should be moved into the builtin help).

Committed: https://crrev.com/189c461d55de98bab1f85abcac8e54203a1b9633
Cr-Commit-Position: refs/heads/master@{#432766}
==========

[commit-bot: I haz the power, 2016-11-17 05:41:10]

Patchset 1 (id:??) landed as
https://crrev.com/189c461d55de98bab1f85abcac8e54203a1b9633
Cr-Commit-Position: refs/heads/master@{#432766}