[vim] Add ninja-powered CrBuild/CrCompileFile functions.

[vim] Add ninja-powered CrBuild/CrCompileFile functions.

These are based on the ninja-build.vim file found in Chromium, adapted
to V8, and enhanced with goma support (automatically increase job limit
for ninja if goma is detected).

Committed: https://crrev.com/b10d55fd34320ed2c6d42836192dbca004b22734
Cr-Commit-Position: refs/heads/master@{#26563}

[Benedikt Meurer, 2015-02-11 06:47:44]

bmeurer@chromium.org changed reviewers:
+ verwaest@chromium.org

[Toon Verwaest, 2015-02-11 06:56:50]

lgtm

[Toon Verwaest, 2015-02-11 06:56:57]

The CQ bit was checked by verwaest@chromium.org

[commit-bot: I haz the power, 2015-02-11 06:57:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/915963002/1

[commit-bot: I haz the power, 2015-02-11 06:59:08]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-11 06:59:23]

Patchset 1 (id:??) landed as
https://crrev.com/b10d55fd34320ed2c6d42836192dbca004b22734
Cr-Commit-Position: refs/heads/master@{#26563}