Measure how many pages are using cross-origin XHR with withCredentials set to true

third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp

Index: third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
diff --git a/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp b/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
index fbc52502f6975d45a687607d728d440bdc28402c..985cda69f98cbbd854c29ad03c8c2db27e8e2bfa 100644
--- a/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
+++ b/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
@@ -874,6 +874,9 @@ void XMLHttpRequest::createRequest(PassRefPtr<EncodedFormData> httpBody, Excepti
 
     m_sameOriginRequest = getSecurityOrigin()->canRequestNoSuborigin(m_url);
 
+    if (m_sameOriginRequest && m_includeCredentials)

[yhirano, 2016/04/14 04:26:02]

!m_sameOriginRequest?

[tyoshino (SeeGerritForStatus), 2016/04/14 04:42:45]

My bad... Fixed

+        UseCounter::count(&executionContext, UseCounter::XMLHttpRequestCrossOriginWithCredentials);
+
     // We also remember whether upload events should be allowed for this request in case the upload listeners are
     // added after the request is started.
     m_uploadEventsAllowed = m_sameOriginRequest || uploadEvents || !FetchUtils::isSimpleRequest(m_method, m_requestHeaders);