https://bugs.webkit.org/show_bug.cgi?id=52343
<rdar://problem/7660558>
        
Reviewed by Darin Adler.

This patch contains the remaining work to support drag and drop on Mac.
I've added a PasteboardTypes class to encapsulate all the pasteboard formats
supported for drag and drop.
In this implementation we don't support the promised types, since I could not
find an efficient way to do this across processes.
The bulk of the patch consists in creating a shareable bitmap for the drag image,
pass its handle to the UI process and create a new NSImage from it to be given to
AppKit for dragging.
I've added the missing implementation of the methods in the drag client to hook
up the placement of the data in the pasteboard.
        
* Shared/mac/PasteboardTypes.h: Added.
* Shared/mac/PasteboardTypes.mm: Added.
(WebKit::PasteboardTypes::forEditing):
(WebKit::PasteboardTypes::forURL):
(WebKit::PasteboardTypes::forImages):
(WebKit::PasteboardTypes::forImagesWithArchive):
* UIProcess/API/mac/PageClientImpl.h:
* UIProcess/API/mac/PageClientImpl.mm:
(WebKit::PageClientImpl::setDragImage): Added.
* UIProcess/API/mac/WKView.mm:
(-[WKView _registerDraggedTypes]): Refactored to use the new PasteboardTypes class.
(-[WKView initWithFrame:contextRef:pageGroupRef:]):
(-[WKView _setMouseDownEvent:]):
(-[WKView _mouseHandler:]):
(-[WKView mouseDown:]):
(-[WKView mouseUp:]):
(-[WKView mouseDragged:]):
(-[WKView draggedImage:endedAt:operation:]):
(-[WKView draggingEntered:]):
(-[WKView _setDragImage:at:linkDrag:]):
* UIProcess/API/mac/WKViewInternal.h:
* UIProcess/PageClient.h:
* UIProcess/WebPageProxy.cpp:
(WebKit::WebPageProxy::setDragImage):
(WebKit::WebPageProxy::dragEnded):
* UIProcess/WebPageProxy.h:
* UIProcess/WebPageProxy.messages.in:
* WebKit2.xcodeproj/project.pbxproj:
* WebProcess/WebCoreSupport/WebDragClient.cpp:
* WebProcess/WebCoreSupport/WebDragClient.h:
* WebProcess/WebCoreSupport/mac/WebDragClientMac.mm: Added.
(WebKit::fontFromNSFont):
(WebKit::WebDragClient::startDrag): Added implementation.
(WebKit::WebDragClient::createDragImageForLink): Ditto.
(WebKit::writeURL): Helper function.
(WebKit::writeImage): Helper function.
(WebKit::WebDragClient::declareAndWriteDragImage): Added implementation.
* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::dragEnded):
* WebProcess/WebPage/WebPage.h:
* WebProcess/WebPage/WebPage.messages.in:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@76186 268f45cc-cd09-0410-ab3c-d52691b4dbfc