Reenable/rebaseline DumpAccessibilityTreeTest.AccessibilityANoText

Reenable/rebaseline DumpAccessibilityTreeTest.AccessibilityANoText

This CL reenables the disabled test:
- DumpAccessibilityTreeTest.AccessibilityANoText.

The test result is rebaselined so that it matches what spec says.
The alttext for failed <img> load should show filename of the src.
http://www.w3.org/TR/1998/REC-html40-19980424/appendix/notes.html#altgen

BUG=448518, 421300
R=dmazzoni@chromium.org

Committed: https://crrev.com/5ad886dd80d7ed7cf8cb7dedbcf9f56531d8c75a
Cr-Commit-Position: refs/heads/master@{#313041}

[kouhei (in TOK), 2015-01-23 05:47:09]

Would you take a look?
This is a follow up to https://codereview.chromium.org/673603002 .

[dmazzoni, 2015-01-23 19:02:28]

lgtm

[kouhei (in TOK), 2015-01-26 01:22:12]

The CQ bit was checked by kouhei@chromium.org

[kouhei (in TOK), 2015-01-26 01:22:18]

On 2015/01/23 19:02:28, dmazzoni wrote:
> lgtm

Thanks!

[commit-bot: I haz the power, 2015-01-26 01:22:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/866373002/1

[commit-bot: I haz the power, 2015-01-26 02:18:24]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-26 02:19:13]

Patchset 1 (id:??) landed as
https://crrev.com/5ad886dd80d7ed7cf8cb7dedbcf9f56531d8c75a
Cr-Commit-Position: refs/heads/master@{#313041}