Combine LayoutObject::previousPaintOffset and paintOffset in paint properties

third_party/WebKit/Source/core/paint/ObjectPaintInvalidator.cpp

 // Copyright 2016 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/paint/ObjectPaintInvalidator.h"
 
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/api/LayoutPartItem.h"
@@ skipping 528 matching lines @@
   // doing a full invalidation.  This is because we need to update the previous
   // selection rect regardless.
   invalidateSelectionIfNeeded(reason);
 
   switch (reason) {
     case PaintInvalidationNone:
       // There are corner cases that the display items need to be invalidated
       // for paint offset mutation, but incurs no pixel difference (i.e. bounds
       // stay the same) so no rect-based invalidation is issued. See
       // crbug.com/508383 and crbug.com/515977.
-      if (m_context.forcedSubtreeInvalidationFlags &
-          PaintInvalidatorContext::ForcedSubtreeInvalidationChecking) {
-        if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
-          if (m_context.oldPaintOffset != m_context.newPaintOffset) {
-            reason = PaintInvalidationLocationChange;
-            break;
-          }
-        } else {
-          // For SPv1, we conservatively assume the object changed paint offset
-          // except for non-root SVG whose paint offset is always zero.
-          if (!m_object.isSVGChild()) {
-            reason = PaintInvalidationLocationChange;
-            break;
-          }
-        }
+      if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled() &&
+          (m_context.forcedSubtreeInvalidationFlags &
+           PaintInvalidatorContext::ForcedSubtreeInvalidationChecking) &&
+          !m_object.isSVGChild()) {
+        // For SPv1, we conservatively assume the object changed paint offset
+        // except for non-root SVG whose paint offset is always zero.
+        reason = PaintInvalidationLocationChange;
+        break;
       }
 
       if (m_object.isSVG() &&
           (m_context.forcedSubtreeInvalidationFlags &
            PaintInvalidatorContext::ForcedSubtreeSVGResourceChange)) {
         reason = PaintInvalidationSVGResourceChange;
         break;
       }
       return PaintInvalidationNone;
     case PaintInvalidationDelayedFull:
       return PaintInvalidationDelayedFull;
     default:
       DCHECK(isImmediateFullPaintInvalidationReason(reason));
       fullyInvalidatePaint(reason, m_context.oldVisualRect,
                            m_context.newVisualRect);
   }
 
   m_context.paintingLayer->setNeedsRepaint();
   m_object.invalidateDisplayItemClients(reason);
   return reason;
 }
 
 DisablePaintInvalidationStateAsserts::DisablePaintInvalidationStateAsserts()
     : m_disabler(&gDisablePaintInvalidationStateAsserts, true) {}
 
 }  // namespace blink