No need to lazily initialize ResourceResponse internals when accessing timing data.
<https://webkit.org/b/134437>
<rdar://problem/17499876>

When building with ENABLE(WEB_TIMING), the last thing that would happen when
serializing a ResourceResponse in the network process is that we'd retrieve
the ResourceLoadTiming to encode it as part of the response. Doing so would
trigger the lazy instantiation of ResourceResponse's internal data structures.

Since timing data is not actually lazily instantiated, we can just not do that.

This shaves off ~550ms of network process main thread time on PLT, reducing
response latency by not doing unnecessary stuff before letting the web process
look at the downloaded data.

Reviewed by Gavin Barraclough.

* WebCore.exp.in:
* platform/network/ResourceResponseBase.cpp:
(WebCore::ResourceResponseBase::adopt):
(WebCore::ResourceResponseBase::resourceLoadTiming): Deleted.
(WebCore::ResourceResponseBase::setResourceLoadTiming): Deleted.
* platform/network/ResourceResponseBase.h:
(WebCore::ResourceResponseBase::resourceLoadTiming):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@170575 268f45cc-cd09-0410-ab3c-d52691b4dbfc