Fix ODR violation that can break WTF::String pretty printing in tests.

Source/modules/websockets/DOMWebSocketTest.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 "config.h"
 #include "modules/websockets/DOMWebSocket.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/V8Binding.h"
 #include "bindings/core/v8/V8BindingForTesting.h"
 #include "core/dom/DOMTypedArray.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/SecurityContext.h"
 #include "core/fileapi/Blob.h"
 #include "core/frame/ConsoleTypes.h"
 #include "core/testing/DummyPageHolder.h"
 #include "platform/heap/Handle.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/Vector.h"
-#include "wtf/testing/WTFTestHelpers.h"
 #include "wtf/text/CString.h"
 #include "wtf/text/WTFString.h"
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 #include <v8.h>
 
 using testing::_;
 using testing::AnyNumber;
 using testing::InSequence;
 using testing::Ref;
@@ skipping 715 matching lines @@
     EXPECT_EQ(InvalidAccessError, m_exceptionState.code());
     EXPECT_EQ(String::format("The code must be either 1000, or between 3000 and 4999. %d is neither.", GetParam()), m_exceptionState.message());
     EXPECT_EQ(DOMWebSocket::CONNECTING, m_websocket->readyState());
 }
 
 INSTANTIATE_TEST_CASE_P(DOMWebSocketInvalidClosingCode, DOMWebSocketInvalidClosingCodeTest, ::testing::Values(0, 1, 998, 999, 1001, 2999, 5000, 9999, 65535));
 
 } // namespace
 
 } // namespace blink