[SPv2] Refactor PaintInvalidator to be multicol-ready.

third_party/WebKit/Source/core/layout/PaintInvalidationState.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 "core/layout/PaintInvalidationState.h"
 
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/layout/LayoutInline.h"
@@ skipping 621 matching lines @@
              << " vs slow: " << slowPathRect.toString();
   showLayoutTree(&m_currentObject);
 
   NOTREACHED();
 }
 
 #endif  // CHECK_FAST_PATH_SLOW_PATH_EQUALITY
 
 PaintInvalidatorContextAdapter::PaintInvalidatorContextAdapter(
     const PaintInvalidationState& paint_invalidation_state)
-    : PaintInvalidatorContext(nullptr),
+    : PaintInvalidatorContext(),
       paint_invalidation_state_(paint_invalidation_state) {
   forced_subtree_invalidation_flags =
       paint_invalidation_state.forced_subtree_invalidation_flags_;
   paint_invalidation_container =
       &paint_invalidation_state.PaintInvalidationContainer();
   painting_layer = &paint_invalidation_state.PaintingLayer();
 }
 
 void PaintInvalidatorContextAdapter::MapLocalRectToVisualRectInBacking(
     const LayoutObject& object,
     LayoutRect& rect) const {
   DCHECK_EQ(&object, &paint_invalidation_state_.CurrentObject());
   paint_invalidation_state_.MapLocalRectToVisualRectInBacking(rect);
 }
 
 }  // namespace blink