Bindings build: split compute_interfaces_info into 2 stages

Bindings build: split compute_interfaces_info into 2 stages

Preparatory refactoring: no changes to generated bindings.

Next step in splitting bindings build is splitting compute_interfaces_info
into core and modules.

For several reasons, I'm *first* splitting the compute_interfaces_info step
into two steps (vertical split): individual and overall.
In follow-up I'll split the individual step in two – core and modules
(horizontal split) – but to keep it simple I'll do that separately.

The reasons are:
1. To treat different IDL files differently, depending on component;
(In follow-up I'll split individual into core vs. modules, and then we'll
finally be able to distinguish components in the CG, and generate qualified
include paths w/o hideous path hacks!)

2. To avoid duplication (we want to avoid reading in all core IDL files for
core, and then reading in all core IDL files *again* and module IDL files for
modules);

3. Simplify build, by having simpler steps.

R=haraken
TBR=Nico
BUG=358074
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=174935

[haraken, 2014-05-28 04:27:44]

LGTM.

[Nils Barth (inactive), 2014-05-28 04:42:47]

The CQ bit was checked by nbarth@chromium.org

[commit-bot: I haz the power, 2014-05-28 04:43:06]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/nbarth@chromium.org/300273005/20001

[commit-bot: I haz the power, 2014-05-28 06:01:37]

Change committed as 174935

[Nils Barth (inactive), 2014-05-28 09:00:37]

On 2014/05/28 06:01:37, I haz the power (commit-bot) wrote:
> Change committed as 174935

This broke run-bindings-tests; fixed in:
Update run-bindings-tests per compute_interfaces_info split
https://codereview.chromium.org/301743008/