Revert of [XHR] Reduce 'readystatechange' event firing.

Revert of [XHR] Reduce 'readystatechange' event firing. (patchset #9 of https://codereview.chromium.org/428473005/)

Reason for revert:
This change breaks legacy applications.

Original issue's description:
> [XHR] Reduce 'readystatechange' event firing.
> 
> Currently too many readystatechange events are fired and
> it hurts performance.
> 
> BUG=336066
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=179381

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=180554

[yhirano, 2014-08-19 08:16:09]

Created Revert of [XHR] Reduce 'readystatechange' event firing.

[commit-bot: I haz the power, 2014-08-19 08:16:35]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/yhirano@chromium.org/486133002/1

[commit-bot: I haz the power, 2014-08-19 08:16:35]

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

[commit-bot: I haz the power, 2014-08-19 08:16:36]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[tkent, 2014-08-19 08:19:49]

The CQ bit was checked by tkent@chromium.org

[tkent, 2014-08-19 08:19:50]

lgtm

[commit-bot: I haz the power, 2014-08-19 08:21:07]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/yhirano@chromium.org/486133002/1

[tyoshino (SeeGerritForStatus), 2014-08-19 10:22:17]

lgtm

https://codereview.chromium.org/486133002/diff/70001/Source/core/xml/XMLHttpR...
File Source/core/xml/XMLHttpRequest.cpp (right):

https://codereview.chromium.org/486133002/diff/70001/Source/core/xml/XMLHttpR...
Source/core/xml/XMLHttpRequest.cpp:443: // Firefox calls readyStateChanged every
time it receives data. Do
Changed -> Change

maybe my mistake...

[yhirano1, 2014-08-19 10:34:51]

https://codereview.chromium.org/486133002/diff/70001/Source/core/xml/XMLHttpR...
File Source/core/xml/XMLHttpRequest.cpp (right):

https://codereview.chromium.org/486133002/diff/70001/Source/core/xml/XMLHttpR...
Source/core/xml/XMLHttpRequest.cpp:443: // Firefox calls readyStateChanged every
time it receives data. Do
On 2014/08/19 10:22:17, tyoshino wrote:
> Changed -> Change
> 
> maybe my mistake...

I will fix it in the future.

[yhirano1, 2014-08-19 10:35:06]

The CQ bit was checked by yhirano@google.com

[commit-bot: I haz the power, 2014-08-19 10:36:04]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/yhirano@chromium.org/486133002/70001

[commit-bot: I haz the power, 2014-08-19 11:42:28]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/23415)

[commit-bot: I haz the power, 2014-08-19 12:22:30]

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

[commit-bot: I haz the power, 2014-08-19 12:22:31]

Try jobs failed on following builders:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/23421)

[yhirano, 2014-08-19 12:46:03]

The CQ bit was checked by yhirano@chromium.org

[commit-bot: I haz the power, 2014-08-19 12:46:24]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/yhirano@chromium.org/486133002/70001

[commit-bot: I haz the power, 2014-08-19 13:28:42]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/23429)

[commit-bot: I haz the power, 2014-08-19 14:09:51]

Committed patchset #2 (70001) as 180554