[Qt] Restore URL Scheme Delegates after QtWebProcess crash

https://bugs.webkit.org/show_bug.cgi?id=108808

When the QtWebProcess crashes, the registered URL Scheme
Delegates are not properly restored over IPC in the newly
launched process instance.

Reviewed by Simon Hausmann.

* UIProcess/API/qt/qquickwebview.cpp:
(QQuickWebViewPrivate::didRelaunchProcess):
(QQuickWebViewPrivate::updateSchemeDelegates):
* UIProcess/API/qt/qquickwebview_p_p.h:
(QQuickWebViewPrivate):

Change-Id: I14493ea1190053e5a523d2cf8a99cc8d526b4fd2
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142997 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>