Make data: urls always parse async

Make data: urls always parse async

Turns out Chrome has long had the behavior of issuing
loads and delivering load events async for data: urls,
but not actually doing the parsing async. This changes
makes the parsing of data:text/html content always async.

NOTE: The new async test (loader/iframe-sync-loads.html)
does not change before before/after this test, it's
there to confirm that we were already behaving async
with regards to when the content appeared in the iframe.

This finally makes it possible to take a JS string
and run it through the HTML parser async.  I'll fix
<iframe srcdoc> to also be async in a follow-up patch.

I wrote a test to check sync/async behavior of various
loading methods for iframes. Gecko has async behavior
for all 3 of these cases in my test, where as Chrome
on Linux has sync behavior for javascript:

This is covered by 3 additional tests:
fast/dom/document-contentType-data-uri.html:
- text/html content is now async, matches FF

accessibility/loading-iframe-sends-notification.html
- had to re-write this test to not assume that the iframe
would be laid out before its onload was fired.

scrollingcoordinator/non-fast-scrollable-region-transformed-iframe.html
- This was hitting crbug.com/365509 which I worked around by
calling setUseMockScrollbars earlier.

browser_tests should have been fixed to expect this change
in https://codereview.chromium.org/257723002/

BUG=308321, 365509
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=172401

[abarth-chromium, 2014-03-25 18:16:29]

lgtm

[commit-bot: I haz the power, 2014-03-25 18:16:36]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eseidel@chromium.org/210253003/1

[commit-bot: I haz the power, 2014-03-25 18:47:50]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-25 18:47:51]

Try jobs failed on following builders:
  tryserver.blink on mac_blink_rel

[eseidel, 2014-03-31 17:37:45]

The CQ bit was checked by eseidel@chromium.org

[commit-bot: I haz the power, 2014-03-31 17:37:46]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eseidel@chromium.org/210253003/1

[commit-bot: I haz the power, 2014-03-31 18:14:29]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-31 18:14:29]

Try jobs failed on following builders:
  tryserver.blink on linux_blink_rel

[eseidel, 2014-04-02 19:36:39]

The CQ bit was checked by eseidel@chromium.org

[commit-bot: I haz the power, 2014-04-02 19:36:49]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eseidel@chromium.org/210253003/1

[commit-bot: I haz the power, 2014-04-02 20:09:40]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-04-02 20:09:41]

Try jobs failed on following builders:
  tryserver.blink on linux_blink_rel

[eseidel, 2014-04-21 17:57:29]

The CQ bit was checked by eseidel@chromium.org

[commit-bot: I haz the power, 2014-04-21 17:57:39]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eseidel@chromium.org/210253003/1

[commit-bot: I haz the power, 2014-04-21 18:33:48]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-04-21 18:33:49]

Try jobs failed on following builders:
  tryserver.blink on linux_blink_rel

[eseidel, 2014-04-21 20:01:06]

The CQ bit was checked by eseidel@chromium.org

[commit-bot: I haz the power, 2014-04-21 20:01:25]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eseidel@chromium.org/210253003/80001

[commit-bot: I haz the power, 2014-04-21 20:34:22]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-04-21 20:34:23]

Try jobs failed on following builders:
  tryserver.blink on linux_blink_rel

[eseidel, 2014-04-22 20:01:24]

PTAL.

Dominic, please check the AX test.

[dmazzoni, 2014-04-22 20:41:23]

lgtm for LayoutTests/accessibility

https://codereview.chromium.org/210253003/diff/100001/LayoutTests/accessibili...
File LayoutTests/accessibility/loading-iframe-sends-notification.html (right):

https://codereview.chromium.org/210253003/diff/100001/LayoutTests/accessibili...
LayoutTests/accessibility/loading-iframe-sends-notification.html:39: // Ignore
this notification if it's not on the iframe.
This should probably say: "Ignore this notification if it's not within the
subtree of the iframe element" or something like that.

https://codereview.chromium.org/210253003/diff/100001/LayoutTests/accessibili...
LayoutTests/accessibility/loading-iframe-sends-notification.html:45:
shouldNotBe("accessibilityController.accessibleElementById('innerbutton')",
"null");
I guess it should not be undefined, but in the world of JS semantics that's the
same

[abarth-chromium, 2014-04-22 22:05:17]

lgtm

[eseidel, 2014-04-22 22:07:58]

The CQ bit was checked by eseidel@chromium.org

[commit-bot: I haz the power, 2014-04-22 22:08:20]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eseidel@chromium.org/210253003/100001

[eseidel, 2014-04-22 22:09:08]

The CQ bit was unchecked by eseidel@chromium.org

[eseidel, 2014-04-22 22:09:08]

The CQ bit was checked by eseidel@chromium.org

[commit-bot: I haz the power, 2014-04-22 22:09:39]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eseidel@chromium.org/210253003/100001

[eseidel, 2014-04-22 22:17:06]

Turns out I haven't quite fixed the AX test.  Changing it to check for undefined
instead revealed that it was failing!

[eseidel, 2014-04-22 22:17:10]

The CQ bit was unchecked by eseidel@chromium.org

[eseidel, 2014-04-22 22:29:38]

The CQ bit was checked by eseidel@chromium.org

[commit-bot: I haz the power, 2014-04-22 22:29:59]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eseidel@chromium.org/210253003/120001

[commit-bot: I haz the power, 2014-04-22 23:37:43]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-04-22 23:37:44]

Try jobs failed on following builders:
  tryserver.blink on linux_blink_dbg

[eseidel, 2014-04-23 00:18:19]

The CQ bit was checked by eseidel@chromium.org

[commit-bot: I haz the power, 2014-04-23 00:18:41]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eseidel@chromium.org/210253003/120001

[commit-bot: I haz the power, 2014-04-23 01:35:17]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-04-23 01:35:18]

Try jobs failed on following builders:
  tryserver.blink on linux_blink_dbg

[eseidel, 2014-04-23 01:40:47]

Looks like a real flake in dbg builds:
https://chromium.googlesource.com/chromium/blink.git/+/f60ed4a0fdfbefd3767229...

Will fix.

[eseidel, 2014-04-23 17:30:16]

The CQ bit was checked by eseidel@chromium.org

[commit-bot: I haz the power, 2014-04-23 17:30:28]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eseidel@chromium.org/210253003/140001

[commit-bot: I haz the power, 2014-04-23 21:09:23]

Change committed as 172401

[aboxhall, 2014-04-23 23:08:04]

A revert of this CL has been created in
https://codereview.chromium.org/259443002/ by aboxhall@chromium.org.

The reason for reverting is: Seems to have broken many browser_tests:
http://build.chromium.org/p/chromium.webkit/builders/Linux%20Tests%20%28dbg%2...
http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_chrome....

[eseidel, 2014-04-24 23:07:17]

I've posted a fix for browser_tests in
https://codereview.chromium.org/257723002/

Once that lands I can re-land this.

[eseidel, 2014-04-28 18:10:19]

I failed to fully fix the browser_tests issues.  I've broken just the LayoutTest
parts of this patch out into https://codereview.chromium.org/258713015/ and will
land those today.  I'm not sure when I'll get back to the rest of this patch.

[dmazzoni, 2014-08-11 05:37:57]

Want to close this?

Removing myself as reviewer for now.

[eseidel, 2014-08-11 05:51:12]

I believe dcheng finished this work.