Analyze support in gyp_webrtc

Analyze support in gyp_webrtc

BUG=chromium:482463
TESTED=Manually tested using the JSON files attached to https://code.google.com/p/chromium/issues/detail?id=482463#c2 and:
webrtc/build/gyp_webrtc --analyzer nothing-files.json nothing-files-RESULT.json
webrtc/build/gyp_webrtc --analyzer everything-files.json everything-files-RESULT.json
webrtc/build/gyp_webrtc --analyzer test_support_unittests-files.json test_support_unittests-files-RESULT.json
Then I verified the result-json contained the expected output.

R=phoglund@webrtc.org

Committed: https://crrev.com/8108764552e20d657c0a6f75a6200b93de486659
Cr-Commit-Position: refs/heads/master@{#10097}

[kjellander_webrtc, 2015-09-25 18:42:26]

kjellander@webrtc.org changed reviewers:
+ phoglund@webrtc.org

[kjellander_webrtc, 2015-09-25 18:44:27]

The argument parsing implementation is kind of ugly but it's a pristine copy of
https://code.google.com/p/chromium/codesearch#chromium/src/build/gyp_chromium...
so I think it's fine. 
Apparently it works.

[phoglund, 2015-09-28 06:42:16]

Myeh, I think it's alright. It's likely to fail ugly if there are too few
arguments, but we can live with that. lgtm

[kjellander_webrtc, 2015-09-28 19:56:58]

Committed patchset #1 (id:1) manually as
8108764552e20d657c0a6f75a6200b93de486659 (presubmit successful).

[commit-bot: I haz the power, 2015-09-28 19:57:01]

Patchset 1 (id:??) landed as
https://crrev.com/8108764552e20d657c0a6f75a6200b93de486659
Cr-Commit-Position: refs/heads/master@{#10097}

[kjellander_webrtc, 2016-02-09 06:44:42]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.webrtc.org/1681023003/ by kjellander@webrtc.org.

The reason for reverting is: I've decided to not aim for implementing analyze
and focus on getting Swarming done instead, so I'm cleaning this up..