Simplify BackgroundImageGeometry by removing meaningless distinctions.

Source/core/paint/BackgroundImageGeometry.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 "core/paint/BackgroundImageGeometry.h"
 
 namespace blink {
 
 void BackgroundImageGeometry::setNoRepeatX(int xOffset)
@@ skipping 13 matching lines @@
 {
     IntPoint alignedPoint = attachmentPoint;
     m_phase.move(std::max(alignedPoint.x() - m_destRect.x(), 0), std::max(alignedPoint.y() - m_destRect.y(), 0));
 }
 
 void BackgroundImageGeometry::clip(const IntRect& clipRect)
 {
     m_destRect.intersect(clipRect);
 }
 
-IntPoint BackgroundImageGeometry::relativePhase() const
-{
-    IntPoint phase = m_phase;
-    phase += m_destRect.location() - m_destOrigin;
-    return phase;
-}
-
 } // namespace blink