[Curl] Add implementation stubs for Network Cache

[Curl] Add implementation stubs for Network Cache
https://bugs.webkit.org/show_bug.cgi?id=181343

Reviewed by Alex Christensen.

* NetworkProcess/cache/NetworkCacheCodersCurl.cpp: Added.
(WTF::Persistence::Coder<WebCore::CertificateInfo>::encode):
(WTF::Persistence::Coder<WebCore::CertificateInfo>::decode):
* NetworkProcess/cache/NetworkCacheDataCurl.cpp: Added.
(WebKit::NetworkCache::Data::Data):
(WebKit::NetworkCache::Data::empty):
(WebKit::NetworkCache::Data::data const):
(WebKit::NetworkCache::Data::isNull const):
(WebKit::NetworkCache::Data::apply const):
(WebKit::NetworkCache::Data::subrange const):
(WebKit::NetworkCache::concatenate):
(WebKit::NetworkCache::Data::adoptMap):
* NetworkProcess/cache/NetworkCacheIOChannelCurl.cpp: Added.
(WebKit::NetworkCache::IOChannel::IOChannel):
(WebKit::NetworkCache::IOChannel::~IOChannel):
(WebKit::NetworkCache::IOChannel::open):
(WebKit::NetworkCache::IOChannel::read):
(WebKit::NetworkCache::IOChannel::write):
* PlatformWin.cmake:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@226465 268f45cc-cd09-0410-ab3c-d52691b4dbfc