The code that pauses animations outside the view does not work for subframes.
<rdar://problem/18001179>
Created attachment 236963 [details] patch
Attachment 236963 [details] did not pass style-queue: ERROR: Source/WebKit/mac/WebView/WebView.mm:1576: The parameter name "view" adds no information, so it should be removed. [readability/parameter_name] [5] ERROR: Source/WebCore/WebCore.exp.in:0: Source/WebCore/WebCore.exp.in should be sorted, use Tools/Scripts/sort-export-file script [list/order] [5] Total errors found: 2 in 12 files If any of these errors are false positives, please file a bug against check-webkit-style.
https://trac.webkit.org/r172854