Remove dead content sniffing code

Source/core/loader/DocumentThreadableLoader.cpp

Index: Source/core/loader/DocumentThreadableLoader.cpp
diff --git a/Source/core/loader/DocumentThreadableLoader.cpp b/Source/core/loader/DocumentThreadableLoader.cpp
index e35f5d25f948c265a3e20887ecadf9623ff73201..96f768a16678b5d2768ff6960de477879e487a5e 100644
--- a/Source/core/loader/DocumentThreadableLoader.cpp
+++ b/Source/core/loader/DocumentThreadableLoader.cpp
@@ -480,10 +480,8 @@ void DocumentThreadableLoader::loadRequest(const ResourceRequest& request, Resou
         resourceLoaderOptions.allowCredentials = DoNotAllowStoredCredentials;
     resourceLoaderOptions.securityOrigin = m_securityOrigin;
     if (m_async) {
-        if (m_actualRequest) {
-            resourceLoaderOptions.sniffContent = DoNotSniffContent;
+        if (m_actualRequest)
             resourceLoaderOptions.dataBufferingPolicy = BufferData;
-        }
 
         if (m_options.timeoutMilliseconds > 0)
             m_timeoutTimer.startOneShot(m_options.timeoutMilliseconds / 1000.0, FROM_HERE);