XMLHttpRequest: Factor out decorder/document init

XMLHttpRequest: Factor out decorder/document init

- |m_createdDocument| renamed to |m_parsedResponse|
- Refactor |didReceiveResponse|:
-- Decoder init factored out into |createDecoder|
- Refactor |responseXML|:
-- Response document init factored out into |initResponseDocument|

Refactoring in preperation to async parsing change.
This patch is split from https://codereview.chromium.org/454313002/

TEST=fast/xmlhttprequest, http/tests/xmlhttprequest
BUG=402261
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=179894

[kouhei (in TOK), 2014-08-10 02:52:50]

Would you take a look?

[abarth-chromium, 2014-08-10 04:49:24]

lgtm

https://codereview.chromium.org/455193002/diff/1/Source/core/xml/XMLHttpReque...
File Source/core/xml/XMLHttpRequest.cpp (right):

https://codereview.chromium.org/455193002/diff/1/Source/core/xml/XMLHttpReque...
Source/core/xml/XMLHttpRequest.cpp:1280: }
No need for { }

[kouhei (in TOK), 2014-08-10 15:40:15]

Thanks for review!

https://codereview.chromium.org/455193002/diff/1/Source/core/xml/XMLHttpReque...
File Source/core/xml/XMLHttpRequest.cpp (right):

https://codereview.chromium.org/455193002/diff/1/Source/core/xml/XMLHttpReque...
Source/core/xml/XMLHttpRequest.cpp:1280: }
On 2014/08/10 04:49:24, abarth wrote:
> No need for { }

Done.

[kouhei (in TOK), 2014-08-10 15:40:18]

The CQ bit was checked by kouhei@chromium.org

[commit-bot: I haz the power, 2014-08-10 15:40:40]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/kouhei@chromium.org/455193002/20001

[commit-bot: I haz the power, 2014-08-10 16:35:07]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  mac_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/mac_blink_rel/builds/19167)

[commit-bot: I haz the power, 2014-08-10 17:06:35]

Change committed as 179894

[tyoshino (SeeGerritForStatus), 2014-08-11 13:20:13]

lgtm