Remove the custom web page preview code

Remove the custom web page preview code
https://bugs.webkit.org/show_bug.cgi?id=139894
<rdar://problem/19333074>

Reviewed by Dan Bernstein.

* UIProcess/API/Cocoa/WKViewPrivate.h:
* UIProcess/API/mac/WKView.mm:
(-[WKView _dismissContentRelativeChildWindows]):
(-[WKView _viewForPreviewingURL:initialFrameSize:]): Deleted.
(-[WKView _titleForPreviewOfURL:]): Deleted.
(-[WKView _setPreviewTitle:]): Deleted.
(-[WKView _setPreviewLoading:]): Deleted.
(-[WKView _setPreviewOverrideImage:]): Deleted.
(-[WKView _finishPreviewingURL:withPreviewView:]): Deleted.
(-[WKView _handleClickInPreviewView:URL:]): Deleted.
(-[WKView _shouldUseStandardQuickLookPreview]): Deleted.
* UIProcess/mac/WKImmediateActionController.h:
* UIProcess/mac/WKImmediateActionController.mm:
(-[WKImmediateActionController willDestroyView:]):
(-[WKImmediateActionController _clearImmediateActionState]):
(-[WKImmediateActionController immediateActionRecognizerWillPrepare:]):
(-[WKImmediateActionController _defaultAnimationController]):
(-[WKImmediateActionController hidePreview]): Deleted.
(-[WKImmediateActionController setPreviewTitle:]): Deleted.
(-[WKImmediateActionController setPreviewLoading:]): Deleted.
(-[WKImmediateActionController setPreviewOverrideImage:]): Deleted.
(-[WKImmediateActionController _animationControllerForCustomPreview]): Deleted.
* UIProcess/mac/WKPagePreviewViewController.h: Removed.
* UIProcess/mac/WKPagePreviewViewController.mm: Removed.
* UIProcess/mac/WKPreviewPopoverAnimationController.h: Removed.
* UIProcess/mac/WKPreviewPopoverAnimationController.mm: Removed.
* WebKit2.xcodeproj/project.pbxproj:
Remove all of the custom web page preview code. Clients that want the custom
preview can implement it by overriding the immediate action.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@177702 268f45cc-cd09-0410-ab3c-d52691b4dbfc