Reviewed by Darin

    Reviewed by Darin

        - fixed <rdar://problem/4794935> setAcceptsMouseMovedEvents: is called for every layout,
          taking ~1% on the PLT test

        * WebView/WebHTMLView.m:
        (-[NSArray layoutToMinimumPageWidth:maximumPageWidth:adjustingViewSize:]):
        Don't call setAcceptsMouseMovedEvents: and WKSetNSWindowShouldPostEventNotifications() here
        because this is called too often.

        * WebView/WebView.m:
        (-[WebView viewWillMoveToWindow:]):
        Do call them here, because this is guaranteed to be called at least once for each window
        containing a webview, but isn't called too often. Also restructured this method a little.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@17162 268f45cc-cd09-0410-ab3c-d52691b4dbfc