https://bugs.webkit.org/show_bug.cgi?id=117944

Reviewed by Anders Carlsson.

In r151877 I polluted Widget with displayID-related stuff. This would
be better on HostWindow, so move it there. This is a net code reduction,
and eliminates PlatformScreenMac.h, and the NSScreen category.

Source/WebCore:

* WebCore.exp.in: Remove some functions from the exports list.
* WebCore.xcodeproj/project.pbxproj: PlatformScreenMac.h is gone!
* dom/Document.cpp:
(WebCore::Document::requestAnimationFrame): Get the displayID from page->chrome()
* page/Chrome.cpp:
(WebCore::Chrome::Chrome): Initialize m_displayID.
(WebCore::Chrome::displayID):
(WebCore::Chrome::windowScreenDidChange): Code moved from Page; save the
displayID, and tell all subframes that the displayID changed.
* page/Chrome.h: Add displayID-related functions.
* page/FrameView.cpp: Removed windowDisplayID().
* page/FrameView.h: Ditto.
* page/Page.cpp: Removed code.
(WebCore::Page::Page):
* page/Page.h:
* platform/HostWindow.h: Added virtual displayID-related functions.
* platform/Widget.cpp: Removed code.
* platform/Widget.h: Ditto.
* platform/mac/PlatformScreenMac.h: Removed.
* platform/mac/PlatformScreenMac.mm: Removed the NSScreen category.
(WebCore::displayIDFromScreen):
(WebCore::screenForDisplayID):
(WebCore::displayFromWidget):
(WebCore::screenForWidget):
* platform/mac/WidgetMac.mm: Removed windowDisplayID().
* rendering/RenderLayerCompositor.cpp:
(WebCore::RenderLayerCompositor::notifyFlushBeforeDisplayRefresh): Get
the displayID via chrome().

Source/WebKit/mac:

* WebView/WebView.mm:
(-[WebView doWindowDidChangeScreen]): Go via chrome().

Source/WebKit2:

* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::windowScreenDidChange): Go via chrome().

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@151926 268f45cc-cd09-0410-ab3c-d52691b4dbfc