Move Notifications APIs from DOMWindow.idl to DOMWindowNotifications.idl

Move Notifications APIs from DOMWindow.idl to DOMWindowNotifications.idl
https://bugs.webkit.org/show_bug.cgi?id=79636

Reviewed by Adam Barth.

For WebKit modularization, this patch moves Notifications-related APIs
from DOMWindow.idl to DOMWindowNotifications.idl.

Tests: fast/notifications/* (No change in test results)

* CMakeLists.txt: Added DOMWindowNotifications.{h,cpp,idl}.
* DerivedSources.make: Ditto.
* DerivedSources.pri: Ditto.
* GNUmakefile.list.am: Ditto.
* Target.pri: Ditto.
* WebCore.gypi: Ditto.
* WebCore.vcproj/WebCore.vcproj: Ditto.

* WebCore.exp.in: Added mangled signatures of webkitNotifications().

* notifications/DOMWindowNotifications.cpp: Added.
(WebCore):
(WebCore::DOMWindowNotifications::DOMWindowNotifications):
(WebCore::DOMWindowNotifications::~DOMWindowNotifications):
(WebCore::DOMWindowNotifications::from):
(WebCore::DOMWindowNotifications::webkitNotifications):
(WebCore::DOMWindowNotifications::ensureWebkitNotifications):
(WebCore::DOMWindowNotifications::disconnectFrame):
* notifications/DOMWindowNotifications.h: Added.
(WebCore):
(DOMWindowNotifications):
* notifications/DOMWindowNotifications.idl: Added.

* page/DOMWindow.cpp: Removed ENABLE(NOTIFICATIONS).
(WebCore::DOMWindow::~DOMWindow):
(WebCore::DOMWindow::willDetachPage):
(WebCore::DOMWindow::clear):
* page/DOMWindow.h: Ditto.
(WebCore):
(DOMWindow):
* page/DOMWindow.idl: Ditto.
* page/Frame.cpp: Ditto.
(WebCore::Frame::willDetachPage):
(WebCore::Frame::transferChildFrameToNewDocument):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@110994 268f45cc-cd09-0410-ab3c-d52691b4dbfc