Reinstate the error code to main content area + bug fixes on security / network interstitials

Error code:
+ Reinstate the error code to main content as important for debugging when screen shots are sent
+ Remove the 'Error code:' prefix on the net error for consistency.

Fixes related to browsing scaling:
+ Remove fixed button height to fix cropped button
+ Fix to incorrectly scaled T-rex

Design:
+ Make the faint tick in checkbox have 0 opacity
+ Fix cropped padlock icon

BUG=460116, 459510, 459126, 458484
Committed: https://crrev.com/b907b0c9264e74fa890318a36bbbe947badda192
Cr-Commit-Position: refs/heads/master@{#318712}

[edwardjung, 2015-02-24 22:34:09]

edwardjung@chromium.org changed reviewers:
+ arv@chromium.org

[edwardjung, 2015-02-24 22:34:10]

Hi Erik, 

Please take a look. Thanks.

Edward

[edwardjung, 2015-02-27 12:55:11]

edwardjung@chromium.org changed reviewers:
+ jhawkins@chromium.org

[edwardjung, 2015-02-27 12:55:12]

James, could you have a look at:
- chrome/app/generated_resources.grd
- chrome/browser/errorpage_browsertest.cc

Erik you're good to look at:
- c/b/resources/security_warnings/*
- c/renderer/resources/*

Thanks.

[arv (Not doing code reviews), 2015-02-27 14:17:59]

LGTM

[James Hawkins, 2015-02-27 15:27:22]

lgtm

[edwardjung, 2015-03-02 17:05:05]

The CQ bit was checked by edwardjung@chromium.org

[commit-bot: I haz the power, 2015-03-02 17:05:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/952563003/140001

[commit-bot: I haz the power, 2015-03-02 17:08:45]

Committed patchset #8 (id:140001)

[commit-bot: I haz the power, 2015-03-02 17:09:39]

Patchset 8 (id:??) landed as
https://crrev.com/b907b0c9264e74fa890318a36bbbe947badda192
Cr-Commit-Position: refs/heads/master@{#318712}