Store previous painting clip rects on FragmentData.

third_party/WebKit/Source/core/layout/LayoutObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1784 matching lines @@
     void SetOnlyThisNeedsPaintPropertyUpdateForTesting() {
       layout_object_.bitfields_.SetNeedsPaintPropertyUpdate(true);
     }
     void ClearNeedsPaintPropertyUpdateForTesting() {
       layout_object_.bitfields_.SetNeedsPaintPropertyUpdate(false);
     }
 #endif
 
    protected:
     friend class PaintPropertyTreeBuilder;
+    friend class PrePaintTreeWalk;
     FRIEND_TEST_ALL_PREFIXES(AnimationCompositorAnimationsTest,
                              canStartAnimationOnCompositorTransformSPv2);
     FRIEND_TEST_ALL_PREFIXES(AnimationCompositorAnimationsTest,
                              canStartAnimationOnCompositorEffectSPv2);
+    FRIEND_TEST_ALL_PREFIXES(PrePaintTreeWalkTest, ClipRects);
 
     // The following non-const functions for ObjectPaintProperties should only
     // be called from PaintPropertyTreeBuilder.
     ObjectPaintProperties& EnsurePaintProperties() {
       return layout_object_.EnsureRarePaintData()
           .EnsureFragment()
           .EnsurePaintProperties();
     }
     ObjectPaintProperties* PaintProperties() {
       if (auto* paint_data = layout_object_.GetRarePaintData())
         return paint_data->PaintProperties();
       return nullptr;
     }
     void ClearPaintProperties() {
       if (auto* paint_data = layout_object_.GetRarePaintData()) {
         if (auto* fragment = paint_data->Fragment())
           fragment->ClearPaintProperties();
       }
     }
+    FragmentData* FirstFragment() {

[wkorman, 2017/05/01 20:29:24]

nit: add brief documentation, and move impl to .cpp file if we can to avoid
having to rebuild the world if/when we modify this later and to make header file
more readable.

[chrishtr, 2017/05/01 21:43:54]

Done.

+      if (auto* paint_data = layout_object_.GetRarePaintData())
+        return paint_data->Fragment();
+      return nullptr;
+    }
 
     // The following non-const functions for local border box properties should
     // only be called from PaintPropertyTreeBuilder.
     void ClearLocalBorderBoxProperties() {
       if (auto* paint_data = layout_object_.GetRarePaintData())
         paint_data->ClearLocalBorderBoxProperties();
     }
     void SetLocalBorderBoxProperties(PropertyTreeState& local_border_box) {
       return layout_object_.EnsureRarePaintData().SetLocalBorderBoxProperties(
           local_border_box);
@@ skipping 980 matching lines @@
 CORE_EXPORT void showLineTree(const blink::LayoutObject*);
 CORE_EXPORT void showLayoutTree(const blink::LayoutObject* object1);
 // We don't make object2 an optional parameter so that showLayoutTree
 // can be called from gdb easily.
 CORE_EXPORT void showLayoutTree(const blink::LayoutObject* object1,
                                 const blink::LayoutObject* object2);
 
 #endif
 
 #endif  // LayoutObject_h