Make an IdlCompiler class

Make an IdlCompiler class

Refactoring CL, inspired by and preliminary to Terry's "speed up r-b-t" CL.
This adds a thin wrapper class, IdlCompiler, which has two methods:
* Initialization (both IdlReader and CodeGeneratorV8)
* .compile()

The resulting main() is v. simple (clear initialization/compile);
this will also make Terry's CL considerably simpler and easier to review,
since he can just instantiate this class in r-b-t and call it repeatedly.

Terry's:
Faster PYTHON IDL dependency computation and parsing.
https://codereview.chromium.org/169743005/

R=haraken

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168340

[Nils Barth (inactive), 2014-03-03 06:39:25]

Quick refactoring CL.

[haraken, 2014-03-03 06:41:52]

LGTM

[Nils Barth (inactive), 2014-03-03 06:48:30]

The CQ bit was checked by nbarth@chromium.org

[commit-bot: I haz the power, 2014-03-03 06:48:37]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/nbarth@chromium.org/178003010/1

[commit-bot: I haz the power, 2014-03-03 09:45:44]

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

[commit-bot: I haz the power, 2014-03-03 09:45:45]

Retried try job too often on win_layout for step(s) webkit_lint
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_layout...

[Nils Barth (inactive), 2014-03-03 23:43:57]

The CQ bit was checked by nbarth@chromium.org

[commit-bot: I haz the power, 2014-03-03 23:44:17]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/nbarth@chromium.org/178003010/1

[commit-bot: I haz the power, 2014-03-03 23:44:38]

Change committed as 168340