in WebKitStatistics leak tracking. By default WebView is not included and
you need to subclass WebView and implement +isIncludedInWebKitStatistics
to be included.

rdar://problem/7567677&7572900
https://webkit.org/b/35045

Reviewed by Adam Roben.

* WebView/WebDataSource.mm:
(-[WebDataSource _initWithDocumentLoader:]): Increment WebDataSourceCount if the WebFrame is included in statistics.
(-[WebDataSource dealloc]): Only --WebDataSourceCount if _private->includedInWebKitStatistics is YES.
(-[WebDataSource finalize]): Ditto.
* WebView/WebFrame.mm:
(-[WebFrame _isIncludedInWebKitStatistics]): Return _private->includedInWebKitStatistics.
(-[WebFrame _initWithWebFrameView:webView:]): Increment WebFrameCount if the WebView's class is included in statistics.
(-[WebFrame dealloc]): Only --WebFrameCount if _private->includedInWebKitStatistics is YES.
(-[WebFrame finalize]): Ditto.
* WebView/WebFrameInternal.h:
* WebView/WebFrameView.mm:
(-[WebFrameView _setWebFrame:]): Increment WebFrameViewCount if the WebFrame is included in statistics.
(-[WebFrameView initWithFrame:]): Move ++WebFrameViewCount from here since we don't
know what WebFrame we belong to yet.
(-[WebFrameView dealloc]): Only --WebFrameViewCount if _private->includedInWebKitStatistics is YES.
(-[WebFrameView finalize]): Ditto.
* WebView/WebHTMLRepresentation.mm:
(-[WebHTMLRepresentation init]): Move ++WebHTMLRepresentationCount from here since we don't
know what WebFrame we belong to yet.
(-[WebHTMLRepresentation dealloc]): Only --WebHTMLRepresentationCount if _private->includedInWebKitStatistics is YES.
(-[WebHTMLRepresentation finalize]): Ditto.
(-[WebHTMLRepresentation setDataSource:]): Increment WebHTMLRepresentationCount if the WebFrame of the dataSource is
included in statistics.
* WebView/WebView.mm:
(-[WebView _commonInitializationWithFrameName:groupName:usesDocumentViews:]):
(-[WebView dealloc]):
(+[WebView shouldIncludeInWebKitStatistics]): Return NO, so any WebView wont be included.
Subclasses that care can return YES to be included.
* WebView/WebViewInternal.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@54908 268f45cc-cd09-0410-ab3c-d52691b4dbfc