Refactor update_w3c_test_expectations.

Refactor update_w3c_test_expectations.

In this CL:
  - Move main() logic into a method in W3CExpectationsLineAdder.
  - Use existing BuildBot instance from host.
  - Make an instance of WebKitFinder in the constructor to avoid
    having to pass it to multiple functions.
  - Decrease the number of args passed around when possible.
  - Make attributes which are referenced in the test non-protected.

Committed: https://crrev.com/bd35b4bf4884541325c0b91f0e8e31249f05457e
Cr-Commit-Position: refs/heads/master@{#414551}

[qyearsley, 2016-08-25 17:22:28]

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

[Dirk Pranke, 2016-08-25 17:27:29]

lgtm

[qyearsley, 2016-08-25 20:36:36]

The CQ bit was checked by qyearsley@chromium.org

[qyearsley, 2016-08-25 20:36:37]

The patchset sent to the CQ was uploaded after l-g-t-m from dpranke@chromium.org
Link to the patchset: https://codereview.chromium.org/2277343002/#ps40001
(title: "Rebased")

[commit-bot: I haz the power, 2016-08-25 20:37:33]

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, 2016-08-25 22:05:58]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-08-25 22:08:23]

Description was changed from

==========
Refactor update_w3c_test_expectations.

In this CL:
  - Move main() logic into a method in W3CExpectationsLineAdder.
  - Use existing BuildBot instance from host.
  - Make an instance of WebKitFinder in the constructor to avoid
    having to pass it to multiple functions.
  - Decrease the number of args passed around when possible.
  - Make attributes which are referenced in the test non-protected.
==========

to

==========
Refactor update_w3c_test_expectations.

In this CL:
  - Move main() logic into a method in W3CExpectationsLineAdder.
  - Use existing BuildBot instance from host.
  - Make an instance of WebKitFinder in the constructor to avoid
    having to pass it to multiple functions.
  - Decrease the number of args passed around when possible.
  - Make attributes which are referenced in the test non-protected.

Committed: https://crrev.com/bd35b4bf4884541325c0b91f0e8e31249f05457e
Cr-Commit-Position: refs/heads/master@{#414551}
==========

[commit-bot: I haz the power, 2016-08-25 22:08:24]

Patchset 3 (id:??) landed as
https://crrev.com/bd35b4bf4884541325c0b91f0e8e31249f05457e
Cr-Commit-Position: refs/heads/master@{#414551}