<rdar://problem/13074829> and https://bugs.webkit.org/show_bug.cgi?id=107974

Reviewed by Alexey Proskuryakov.

Some of this patch is refactoring to enable more flexibility in the authentication mechanism
and the rest is actually implementing Network->UI process authentication.

Expose the same AuthenticationManager to anyone in the NetworkProcess asking for it:
* NetworkProcess/NetworkProcess.cpp:
(WebKit::NetworkProcess::authenticationManager):
(WebKit::NetworkProcess::downloadsAuthenticationManager):
* NetworkProcess/NetworkProcess.h:

* NetworkProcess/NetworkResourceLoader.cpp:
(WebKit::NetworkResourceLoader::didReceiveAuthenticationChallenge): Instead of messaging to
  the WebProcess, tell the NetworkProcess AuthenticationManager.

Add WebPageID and WebFrameID members to SchedulableLoader that they receive from
* NetworkProcess/SchedulableLoader.cpp:
* NetworkProcess/SchedulableLoader.h:
(WebKit::SchedulableLoader::webPageID):
(WebKit::SchedulableLoader::webFrameID):

Add a 3rd form of "didReceiveAuthenticationChallenge" for NetworkProcess use:
* Shared/Authentication/AuthenticationManager.cpp:
(WebKit::AuthenticationManager::mapChallengeToIdentifier):
(WebKit::AuthenticationManager::didReceiveAuthenticationChallenge):
* Shared/Authentication/AuthenticationManager.h:
* Shared/Authentication/mac/AuthenticationManager.mac.mm:
(WebKit::AuthenticationManager::tryUsePlatformCertificateInfoForChallenge): Remove a now obsolete comment

Include the WebPage and WebFrame ID for the originator of this request in case it results in a challenge:
* Shared/Network/NetworkResourceLoadParameters.cpp:
(WebKit::NetworkResourceLoadParameters::NetworkResourceLoadParameters):
(WebKit::NetworkResourceLoadParameters::encode):
(WebKit::NetworkResourceLoadParameters::decode):
* Shared/Network/NetworkResourceLoadParameters.h:
(WebKit::NetworkResourceLoadParameters::webPageID):
(WebKit::NetworkResourceLoadParameters::webFrameID):

Create a AuthenticationChallengeProxy pointing back to the NetworkProcess (instead of a WebProcess),
and send the challenge to the appropriate WebPageProxy:
* UIProcess/Network/NetworkProcessProxy.cpp:
(WebKit::NetworkProcessProxy::didReceiveAuthenticationChallenge):
* UIProcess/Network/NetworkProcessProxy.h:
* UIProcess/Network/NetworkProcessProxy.messages.in:

Refactor didReceiveAuthenticationChallenge so an outsider can directly hand over an AuthenticationChallengeProxy:
* UIProcess/WebPageProxy.cpp:
(WebKit::WebPageProxy::didReceiveAuthenticationChallenge):
(WebKit::WebPageProxy::didReceiveAuthenticationChallengeProxy):
* UIProcess/WebPageProxy.h:

Add a global WebPageID -> WebPageProxy map so parties with an ID don't need to know which process it belongs to:
* UIProcess/WebProcessProxy.cpp:
(WebKit::globalPageMap):
(WebKit::WebProcessProxy::webPage):
(WebKit::WebProcessProxy::createWebPage):
(WebKit::WebProcessProxy::addExistingWebPage):
(WebKit::WebProcessProxy::removeWebPage):
* UIProcess/WebProcessProxy.h:

* WebProcess/Network/WebResourceLoadScheduler.cpp:
(WebKit::WebResourceLoadScheduler::scheduleLoad):

* WebProcess/WebCoreSupport/WebPlatformStrategies.cpp:
(WebKit::WebPlatformStrategies::loadResourceSynchronously): Pass 0 for WebFrameID and WebPageID since synchronous
  loads don't go through "normal" authentication channels and don't need them. Yet.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@140874 268f45cc-cd09-0410-ab3c-d52691b4dbfc