[SPInvalidation, SPv2] Compute paint offset for paginated content

third_party/WebKit/Source/core/paint/PaintInvalidator.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/PaintInvalidator.h"
 
 #include "core/editing/FrameSelection.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
@@ skipping 425 matching lines @@
   object.GetMutableForPainting().EnsureIsReadyForPaintInvalidation();
 
   UpdatePaintingLayer(object, context);
 
   if (object.GetDocument().Printing() &&
       !RuntimeEnabledFeatures::printBrowserEnabled())
     return;  // Don't invalidate paints if we're printing.
 
   // TODO(crbug.com/637313): Use GeometryMapper which now supports filter
   // geometry effects, after skia optimizes filter's mapRect operation.
-  // TODO(crbug.com/648274): This is a workaround for multi-column contents.
+  // Multi-column requires the slow path. See crbug.com/648274).
   if (object.HasFilterInducingProperty() || object.IsLayoutFlowThread()) {
     context.forced_subtree_invalidation_flags |=
         PaintInvalidatorContext::kForcedSubtreeSlowPathRect;
   }
 
   UpdatePaintInvalidationContainer(object, context);
   UpdateVisualRectIfNeeded(object, context);
 
   if (!object.ShouldCheckForPaintInvalidation() &&
       !(context.forced_subtree_invalidation_flags &
@@ skipping 48 matching lines @@
 }
 
 void PaintInvalidator::ProcessPendingDelayedPaintInvalidations() {
   for (auto target : pending_delayed_paint_invalidations_) {
     target->GetMutableForPainting().SetShouldDoFullPaintInvalidation(
         kPaintInvalidationDelayedFull);
   }
 }
 
 }  // namespace blink