../../Source/WebCore/Modules/fetch/FetchHeaders.h:102:8: warning: base class ‘class WTF::RefCounted<WebCore::FetchHeaders>’ should be explicitly initialized in the copy constructor [-Wextra] inline FetchHeaders::FetchHeaders(const FetchHeaders& other) ^~~~~~~~~~~~
Fixed in r220054. https://trac.webkit.org/changeset/220054/webkit
<rdar://problem/33619685>