_userInitiated is always NO in WKNavigationAction passed to -webView:createWebViewWithConfiguration:forNavigationAction:windowFeatures:
The reason it’s NO is that the value is decided based on ScriptController::processingUserGesture() at the time WebChromeClient::createWindow() is called, which is only after the policy decision has been made. By then, processingUserGesture() is false.
Created attachment 229516 [details]
Add and use a processionUserGesture flag on NavigationAction
Attachment 229516 [details] did not pass style-queue:
ERROR: Source/WebCore/loader/NavigationAction.cpp:75: Wrong number of spaces before statement. (expected: 12) [whitespace/indent] 
ERROR: Source/WebCore/loader/NavigationAction.cpp:92: Wrong number of spaces before statement. (expected: 12) [whitespace/indent] 
Total errors found: 2 in 6 files
If any of these errors are false positives, please file a bug against check-webkit-style.
Fixed in <http://trac.webkit.org/r167425>.