send notifications appropriate times (showing up, resizing)
-and corresponding-
https://bugs.webkit.org/show_bug.cgi?id=56067

Reviewed by Darin Adler.

The general strategy here is to add a HashSet of ScrollableAreas to the page that 
can be accessed when necessary to send notifications to all ScrollableAreas.

Find layers for relevant node and if the layers are in the Page's ScrollableArea 
set, then send the relevant notification.
* page/EventHandler.cpp:
(WebCore::EventHandler::mouseMoved):
(WebCore::EventHandler::updateMouseEventTargetNode):

When the page is set active or not active, iterate through the Page's 
ScrollableAreas to send hide/show notifications. 
* page/FocusController.cpp:
(WebCore::FocusController::setActive):

When a FrameView is created, add it to the ScrollableArea set. When it's 
destroyed, remove it.
* page/FrameView.cpp:
(WebCore::FrameView::FrameView):
(WebCore::FrameView::~FrameView):

Iterate through the Page's ScrollableAreas to send the paint notification.
(WebCore::FrameView::notifyPageThatContentAreaWillPaint):
* page/FrameView.h:

Add the new ScrollableArea set.
* page/Page.cpp:
(WebCore::Page::addScrollableArea):
(WebCore::Page::removeScrollableArea):
(WebCore::Page::pageContainsScrollableArea):
* page/Page.h:
(WebCore::Page::scrollableAreaSet):

notifyPageThatContentAreaWillPaint() is a dummy function implemented in FrameView.
* platform/ScrollView.cpp:
(WebCore::ScrollView::notifyPageThatContentAreaWillPaint):

Call notifyPageThatContentAreaWillPaint() instead of calling 
contentAreaWillPaint() just for the ScrollView.
(WebCore::ScrollView::paint):
* platform/ScrollView.h:

Add/remove ScrollableAreas to the set.
* rendering/RenderDataGrid.cpp:
(WebCore::RenderDataGrid::RenderDataGrid):
(WebCore::RenderDataGrid::~RenderDataGrid):
* rendering/RenderListBox.cpp:
(WebCore::RenderListBox::RenderListBox):
(WebCore::RenderListBox::~RenderListBox):
* rendering/RenderLayer.cpp:
(WebCore::RenderLayer::RenderLayer):
(WebCore::RenderLayer::~RenderLayer):

Should have implemented this ScrollableArea-interface function a while ago.
(WebCore::RenderLayer::currentMousePosition):
* rendering/RenderLayer.h:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@80800 268f45cc-cd09-0410-ab3c-d52691b4dbfc