Literal AtomicString construction can rely on strlen optimization.

third_party/WebKit/Source/modules/fetch/RequestInit.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 "modules/fetch/RequestInit.h"
 
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/V8ArrayBuffer.h"
 #include "bindings/core/v8/V8ArrayBufferView.h"
 #include "bindings/core/v8/V8Binding.h"
@@ skipping 61 matching lines @@
     } else if (v8Body->IsArrayBufferView()) {
         body = FetchFormDataConsumerHandle::create(V8ArrayBufferView::toImpl(v8::Local<v8::Object>::Cast(v8Body)));
     } else if (V8Blob::hasInstance(v8Body, isolate)) {
         RefPtr<BlobDataHandle> blobDataHandle = V8Blob::toImpl(v8::Local<v8::Object>::Cast(v8Body))->blobDataHandle();
         contentType = blobDataHandle->type();
         body = FetchBlobDataConsumerHandle::create(context, blobDataHandle.release());
     } else if (V8FormData::hasInstance(v8Body, isolate)) {
         RefPtr<EncodedFormData> formData = V8FormData::toImpl(v8::Local<v8::Object>::Cast(v8Body))->encodeMultiPartFormData();
         // Here we handle formData->boundary() as a C-style string. See
         // FormDataEncoder::generateUniqueBoundaryString.
-        contentType = AtomicString("multipart/form-data; boundary=", AtomicString::ConstructFromLiteral) + formData->boundary().data();
+        contentType = AtomicString("multipart/form-data; boundary=") + formData->boundary().data();
         body = FetchFormDataConsumerHandle::create(context, formData.release());
     } else if (V8URLSearchParams::hasInstance(v8Body, isolate)) {
         RefPtr<EncodedFormData> formData = V8URLSearchParams::toImpl(v8::Local<v8::Object>::Cast(v8Body))->encodeFormData();
-        contentType = AtomicString("application/x-www-form-urlencoded;charset=UTF-8", AtomicString::ConstructFromLiteral);
+        contentType = AtomicString("application/x-www-form-urlencoded;charset=UTF-8");
         body = FetchFormDataConsumerHandle::create(context, formData.release());
     } else if (V8PasswordCredential::hasInstance(v8Body, isolate)) {
         // See https://w3c.github.io/webappsec-credential-management/#monkey-patching-fetch-4
         // and https://w3c.github.io/webappsec-credential-management/#monkey-patching-fetch-3
         isCredentialRequest = true;
         PasswordCredential* credential = V8PasswordCredential::toImpl(v8::Local<v8::Object>::Cast(v8Body));
 
         RefPtr<EncodedFormData> encodedData = credential->encodeFormData(contentType);
         body = FetchFormDataConsumerHandle::create(context, encodedData.release());
     } else if (v8Body->IsString()) {
         contentType = "text/plain;charset=UTF-8";
         body = FetchFormDataConsumerHandle::create(toUSVString(isolate, v8Body, exceptionState));
     }
 }
 
 } // namespace blink