Consider "mixed content XHR" as mixed script instead of mixed display.

Source/core/xml/XMLHttpRequest.cpp

Index: Source/core/xml/XMLHttpRequest.cpp
diff --git a/Source/core/xml/XMLHttpRequest.cpp b/Source/core/xml/XMLHttpRequest.cpp
index 645c48a8bb15103b967623c7babbd700875311c1..db05606f5d5b22c9106ce7d2669bfb2ce75c41db 100644
--- a/Source/core/xml/XMLHttpRequest.cpp
+++ b/Source/core/xml/XMLHttpRequest.cpp
@@ -748,6 +748,7 @@ void XMLHttpRequest::createRequest(ExceptionState& es)
     options.securityOrigin = securityOrigin();
     options.initiator = FetchInitiatorTypeNames::xmlhttprequest;
     options.contentSecurityPolicyEnforcement = ContentSecurityPolicy::shouldBypassMainWorld(scriptExecutionContext()) ? DoNotEnforceContentSecurityPolicy : EnforceConnectSrcDirective;
+    options.mixedContentBlockingTreatment = TreatAsActiveContent;
     options.timeoutMilliseconds = m_timeoutMilliseconds;
 
     m_exceptionCode = 0;