More work on UI side local storage
https://bugs.webkit.org/show_bug.cgi?id=108119

Reviewed by Beth Dakin.

* WebKit2.xcodeproj/project.pbxproj:
* WebProcess/Storage/StorageNamespaceProxy.cpp:
(WebKit::StorageNamespaceProxy::createSessionStorageNamespace):
Rename create to createSessionStorageNamespace and make it take a WebPage.

(WebKit::StorageNamespaceProxy::StorageNamespaceProxy):
Add WebPage parameter.

* WebProcess/WebCoreSupport/WebPlatformStrategies.cpp:
(WebKit::WebPlatformStrategies::sessionStorageNamespace):
Add an #ifdef for enabling UI side storage.

* WebProcess/WebPage/WebFrame.cpp:
(WebKit::WebFrame::page):
Call new WebPage::fromCorePage helper.

* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::fromCorePage):
Add new function for getting a WebPage from a WebCore::Page.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141017 268f45cc-cd09-0410-ab3c-d52691b4dbfc