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

Source/core/editing/GranularityStrategyTest.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 "bindings/core/v8/ExceptionStatePlaceholder.h"
 #include "core/HTMLNames.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/Text.h"
 #include "core/editing/FrameSelection.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLBodyElement.h"
 #include "core/html/HTMLDocument.h"
 #include "core/testing/DummyPageHolder.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefPtr.h"
 #include "wtf/StdLibExtras.h"
-#include "wtf/testing/WTFTestHelpers.h"
 #include <gtest/gtest.h>
 
 namespace blink {
 
 #define EXPECT_EQ_SELECTED_TEXT(text) \
     EXPECT_EQ(text, WebString(selection().selectedText()).utf8())
 
 IntPoint visiblePositionToContentsPoint(const VisiblePosition& pos)
 {
     IntPoint result = pos.absoluteCaretBounds().minXMaxYCorner();
@@ skipping 620 matching lines @@
 
     // "ab cd efghijkl ^mnopqr |>stuvwi inm," (^ means base and | means extent,
     // > means end).
     selection().setSelection(VisibleSelection(Position(text, 15), Position(text, 22)));
     EXPECT_EQ_SELECTED_TEXT("mnopqr ");
     selection().moveRangeSelectionExtent(m_wordMiddles[4]);
     EXPECT_EQ_SELECTED_TEXT("mnopqr iiin");
 }
 
 } // namespace blink