Literal AtomicString construction can rely on strlen optimization.

third_party/WebKit/Source/core/loader/BeaconLoader.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/loader/BeaconLoader.h"
 
 #include "core/dom/DOMArrayBufferView.h"
 #include "core/dom/Document.h"
 #include "core/fetch/CrossOriginAccessControl.h"
 #include "core/fetch/FetchContext.h"
@@ skipping 211 matching lines @@
 }
 
 bool Beacon::serialize(FormData* data, ResourceRequest& request, int allowance, int& payloadLength)
 {
     ASSERT(data);
     RefPtr<EncodedFormData> entityBody = data->encodeMultiPartFormData();
     unsigned long long entitySize = entityBody->sizeInBytes();
     if (allowance > 0 && static_cast<unsigned long long>(allowance) < entitySize)
         return false;
 
-    AtomicString contentType = AtomicString("multipart/form-data; boundary=", AtomicString::ConstructFromLiteral) + entityBody->boundary().data();
+    AtomicString contentType = AtomicString("multipart/form-data; boundary=") + entityBody->boundary().data();
     request.setHTTPBody(entityBody.release());
     request.setHTTPContentType(contentType);
 
     payloadLength = entitySize;
     return true;
 }
 
 } // namespace
 
 } // namespace blink