CSP: 'frame-ancestors' should override 'x-frame-options'.

Source/core/frame/csp/ContentSecurityPolicy.cpp

Index: Source/core/frame/csp/ContentSecurityPolicy.cpp
diff --git a/Source/core/frame/csp/ContentSecurityPolicy.cpp b/Source/core/frame/csp/ContentSecurityPolicy.cpp
index 78d708fbd1658383281944db8bd972ba7965c3d3..2fea03c2834cb155ec5e940e614342431777f166 100644
--- a/Source/core/frame/csp/ContentSecurityPolicy.cpp
+++ b/Source/core/frame/csp/ContentSecurityPolicy.cpp
@@ -615,6 +615,15 @@ bool ContentSecurityPolicy::allowAncestors(LocalFrame* frame, const KURL& url, C
     return isAllowedByAllWithFrame<&CSPDirectiveList::allowAncestors>(m_policies, frame, url, reportingStatus);
 }
 
+bool ContentSecurityPolicy::isFrameAncestorsEnforced() const
+{
+    for (const auto& policy : m_policies) {
+        if (policy->isFrameAncestorsEnforced())
+            return true;
+    }
+    return false;
+}
+
 bool ContentSecurityPolicy::isActive() const
 {
     return !m_policies.isEmpty();