Web process should decide when to continue main resource loads

https://bugs.webkit.org/show_bug.cgi?id=114995

Reviewed by Sam Weinig.

Main resource loads can be converted to downloads, so we need the ability to let the web process decide when
to continue loading after a response has been received.

* NetworkProcess/NetworkResourceLoader.cpp:
(WebKit::NetworkResourceLoader::didReceiveResponseAsync):
For non-main resources, just call continueDidReceiveResponse directly; there's no need to ping-pong to the web process in that case.

(WebKit::NetworkResourceLoader::continueDidReceiveResponse):
Just call ResourceHandle::continueDidReceiveResponse.

* NetworkProcess/NetworkResourceLoader.messages.in:
Add ContinueDidReceiveResponse message.

* NetworkProcess/SchedulableLoader.cpp:
(WebKit::SchedulableLoader::SchedulableLoader):
Initialize m_isLoadingMainResource.

* NetworkProcess/SchedulableLoader.h:
(WebKit::SchedulableLoader::isLoadingMainResource):
Add getter.

(SchedulableLoader):
Move m_shouldClearReferrerOnHTTPSToHTTPRedirect next to the rest of the booleans.

* Shared/Network/NetworkResourceLoadParameters.cpp:
(WebKit::NetworkResourceLoadParameters::NetworkResourceLoadParameters):
(WebKit::NetworkResourceLoadParameters::encode):
(WebKit::NetworkResourceLoadParameters::decode):
* Shared/Network/NetworkResourceLoadParameters.h:
(NetworkResourceLoadParameters):
Add isMainResource flag.

* WebProcess/Network/WebResourceLoadScheduler.cpp:
(WebKit::WebResourceLoadScheduler::scheduleSubresourceLoad):
Pass the cached resource to scheduleLoad.

(WebKit::WebResourceLoadScheduler::schedulePluginStreamLoad):
Pass null to scheduleLoad.

(WebKit::WebResourceLoadScheduler::scheduleLoad):
Initialize isMainResource.

* WebProcess/Network/WebResourceLoader.cpp:
(WebKit::WebResourceLoader::didReceiveResponseWithCertificateInfo):
If this is a main resource load, send back a ContinueDidReceiveResponse message.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@148922 268f45cc-cd09-0410-ab3c-d52691b4dbfc