Ensure the event's default handler is triggered in the same way as it is
during a PlatformWheelEvent.

Patch by Andy Estes <aestes@apple.com> on 2010-03-02
Reviewed by Maciej Stachowiak.

https://bugs.webkit.org/show_bug.cgi?id=35566

Test: fast/events/wheelevent-in-scrolling-div.html

* dom/Node.cpp: Ensure that the default behavior (scrolling) occurs for
wheel events originating both from the platform and from
JavaScript/ObjC.
(WebCore::Node::dispatchWheelEvent): Instantiate new WheelEvent with
the graunularity of the PlatformWheelEvent.
(WebCore::Node::defaultEventHandler): Add support for mousewheel events.
* dom/WheelEvent.cpp: Add three new member variables: m_deltaX, m_deltaY
and m_granularity.  m_deltaX and m_deltaY differ from m_wheelDeltaX and
m_wheelDeltaY, which are the number of wheel ticks multiplied by 120 for
IE compatibility.
(WebCore::WheelEvent::WheelEvent): Initialize new member variables.
(WebCore::WheelEvent::initWheelEvent): Same.
(WebCore::WheelEvent::initWebKitWheelEvent): Same.
* dom/WheelEvent.h: See WheelEvent.cpp.
(WebCore::WheelEvent::): Add Granularity enum (Pixel, Line, Page).
(WebCore::WheelEvent::create): Add new arguments.
(WebCore::WheelEvent::deltaX): Amount of scroll in x direction.
(WebCore::WheelEvent::deltaY): Amount of scroll in y direction.
(WebCore::WheelEvent::granularity): Units of deltaX and deltaY.
* dom/WheelEvent.idl: Add initWebKitWheelEvent() to JavaScript.  This is
the same as the initWheelEvent ObjC method.  As the DOM Level 3 Events
specification is still a working draft and subject to change, prefix
'WebKit' to the method signature to indicate experimental support.
* page/EventHandler.cpp: Move the scroll handling from
handleWheelEvent() to defaultWheelEventHandler(), which is executed on
both PlatformWheelEvents and JavaScript WheelEvents.
(WebCore::scrollNode): Renamed from scrollAndAcceptEvent().  Remove
the PlatformWheelEvent from the argument list and instead return a
boolean indicating if the scroll event was accepted.
(WebCore::EventHandler::handleWheelEvent): Move scrolling code from here
(WebCore::EventHandler::defaultWheelEventHandler): ...to here.
* page/EventHandler.h: Add function signature.

LayoutTests: Add a test for the patch to https://bugs.webkit.org/show_bug.cgi?id=35566.
These can be run manually or from DRT.

Patch by Andy Estes <aestes@apple.com> on 2010-03-02
Reviewed by Maciej Stachowiak.

* fast/events/wheelevent-in-scrolling-div-expected.txt: Added.
* fast/events/wheelevent-in-scrolling-div.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@55436 268f45cc-cd09-0410-ab3c-d52691b4dbfc