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..90295c70426d10ec679ce27ba9922a868a4844c7 100644
--- a/Source/core/xml/XMLHttpRequest.cpp
+++ b/Source/core/xml/XMLHttpRequest.cpp
@@ -486,6 +486,14 @@ void XMLHttpRequest::setWithCredentials(bool value, ExceptionState& exceptionSta
         return;
     }
 
+    // FIXME: According to XMLHttpRequest Level 2 we should throw InvalidAccessError exception here.
+    // However for time being only throw warning message to console to give web developers time to update.
+    if (!m_async && executionContext()->isDocument()) {
+        String consoleMessage("Support for withCredentials deprecated for synchronous requests.");

[Inactive, 2014/06/12 13:28:39]

If you do this, you will like need to add a UseCounter as well so that we can
measure usage out there and know if and when it is safe to drop support for
this.

+        executionContext()->addConsoleMessage(JSMessageSource, WarningMessageLevel, consoleMessage);
+        return;
+    }
+
     m_includeCredentials = value;
 }