Deprecate support for xhr.withCredentials for synchronous requests

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 3befd8e2073a228de6f5b8b423db4ba35ff31784..83070e02159b43fb4dc9cb65d53a591505d777e2 100644
--- a/Source/core/xml/XMLHttpRequest.cpp
+++ b/Source/core/xml/XMLHttpRequest.cpp
@@ -36,6 +36,8 @@
 #include "core/fileapi/Blob.h"
 #include "core/fileapi/File.h"
 #include "core/fileapi/Stream.h"
+#include "core/frame/Settings.h"
+#include "core/frame/UseCounter.h"
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "core/html/DOMFormData.h"
 #include "core/html/HTMLDocument.h"
@@ -43,7 +45,6 @@
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/inspector/InspectorTraceEvents.h"
 #include "core/loader/ThreadableLoader.h"
-#include "core/frame/Settings.h"
 #include "core/xml/XMLHttpRequestProgressEvent.h"
 #include "core/xml/XMLHttpRequestUpload.h"
 #include "platform/Logging.h"
@@ -486,6 +487,11 @@ void XMLHttpRequest::setWithCredentials(bool value, ExceptionState& exceptionSta
         return;
     }
 
+    // FIXME: According to XMLHttpRequest Level 2 we should throw InvalidAccessError exception here.

[eseidel, 2014/06/16 23:23:51]

Seems like we should only bother to print this deprecation if sites are actually
changing the value from its default?

[Inactive, 2014/06/17 00:02:22]

Eric, the idea is to eventually match the spec and start throwing if m_async is
false (no matter what value is being assigned). As a result, I think it makes
sense to display the deprecation message, no matter what value is being set as
we would break those pages if we started throwing. Do you agree?

P.S: You status still says "OOO" :)

[tyoshino (SeeGerritForStatus), 2014/06/17 02:19:49]

Sounds good. Otherwise, we should fix the spec first.

+    // However for time being only print warning message to warn web developers.
+    if (!m_async && executionContext()->isDocument())
+        UseCounter::countDeprecation(document(), UseCounter::SyncXHRWithCredentials);
+
     m_includeCredentials = value;
 }