Move NetworkProcess/Classifier/ResourceLoadStatisticsStoreCocoa.mm functionality...

Move NetworkProcess/Classifier/ResourceLoadStatisticsStoreCocoa.mm functionality into UIProcess/WebsiteData/Cocoa/WebsiteDataStoreCocoa.mm
https://bugs.webkit.org/show_bug.cgi?id=195117
<rdar://problem/48448715>

Reviewed by Brent Fulgham.

Reading of user defaults on Cocoa platforms should be done in the UI process and
forwarded to Resource Load Statistics in the network process through the
WebKit::NetworkSessionCreationParameters struct.

This patch does away with some old user defaults we don't use anymore. It also
changes the developer-facing default name to ITPManualPrevalentResource.

* NetworkProcess/Classifier/ResourceLoadStatisticsDatabaseStore.cpp:
(WebKit::ResourceLoadStatisticsDatabaseStore::ResourceLoadStatisticsDatabaseStore):
    Removed the call to the old registerUserDefaultsIfNeeded().
* NetworkProcess/Classifier/ResourceLoadStatisticsMemoryStore.cpp:
(WebKit::ResourceLoadStatisticsMemoryStore::ResourceLoadStatisticsMemoryStore):
    Removed the call to the old registerUserDefaultsIfNeeded().
* NetworkProcess/Classifier/ResourceLoadStatisticsStore.h:
    Removed the declaration of the old registerUserDefaultsIfNeeded().
* NetworkProcess/Classifier/ResourceLoadStatisticsStoreCocoa.mm: Removed.
* NetworkProcess/Classifier/WebResourceLoadStatisticsStore.h:
    Added an enum class EnableResourceLoadStatisticsDebugMode.
* NetworkProcess/NetworkSession.cpp:
(WebKit::NetworkSession::setResourceLoadStatisticsEnabled):
* NetworkProcess/NetworkSession.h:
* NetworkProcess/NetworkSessionCreationParameters.cpp:
(WebKit::NetworkSessionCreationParameters::encode const):
(WebKit::NetworkSessionCreationParameters::decode):
* NetworkProcess/NetworkSessionCreationParameters.h:
   The struct now has two new fields:
   - enableResourceLoadStatisticsDebugMode
   - resourceLoadStatisticsManualPrevalentResource
* NetworkProcess/cocoa/NetworkSessionCocoa.mm:
(WebKit::NetworkSessionCocoa::NetworkSessionCocoa):
    Forwarding of the parameters.
* SourcesCocoa.txt:
* UIProcess/WebProcessPool.cpp:
(WebKit::WebProcessPool::ensureNetworkProcess):
    Forwarding of the parameters.
* UIProcess/WebsiteData/Cocoa/WebsiteDataStoreCocoa.mm:
(WebKit::WebsiteDataStore::parameters):
    This is where user defaults for Resource Load Statistics are now read.
* WebKit.xcodeproj/project.pbxproj:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@242764 268f45cc-cd09-0410-ab3c-d52691b4dbfc