Move PreviousBoxGeometries from BoxPaintInvalidator into LayoutBox::m_rareData

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

Index: third_party/WebKit/Source/core/layout/LayoutBox.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.h b/third_party/WebKit/Source/core/layout/LayoutBox.h
index ca26cdbff78eeb24b3482ae0b87951d8a4fbbdd2..70b464a08157adc3e357ee76d20c818b7adcbcee 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.h
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.h
@@ -76,8 +76,10 @@ struct LayoutBoxRareData {
   LayoutUnit m_overrideLogicalContentWidth;
   LayoutUnit m_overrideLogicalContentHeight;
 
-  bool m_hasOverrideContainingBlockContentLogicalWidth;
-  bool m_hasOverrideContainingBlockContentLogicalHeight;
+  bool m_hasOverrideContainingBlockContentLogicalWidth : 1;
+  bool m_hasOverrideContainingBlockContentLogicalHeight : 1;
+  bool m_hasPreviousOtherBoxGeometries : 1;
+
   LayoutUnit m_overrideContainingBlockContentLogicalWidth;
   LayoutUnit m_overrideContainingBlockContentLogicalHeight;
 
@@ -98,6 +100,12 @@ struct LayoutBoxRareData {
 
     return *m_snapAreas;
   }
+
+  // Used by BoxPaintInvalidator. Stores the previous content box size and
+  // layout overflow rect after the last paint invalidation.
+  // These are valid if m_hasPreviousOtherBoxGeometries is true.
+  LayoutSize m_previousContentBoxSize;
+  LayoutRect m_previousLayoutOverflowRect;
 };
 
 // LayoutBox implements the full CSS box model.
@@ -318,7 +326,6 @@ class CORE_EXPORT LayoutBox : public LayoutBoxModelObject {
     return LayoutSize(m_frameRect.x(), m_frameRect.y());
   }
   LayoutSize size() const { return m_frameRect.size(); }
-  LayoutSize previousSize() const { return m_previousSize; }
   IntSize pixelSnappedSize() const { return m_frameRect.pixelSnappedSize(); }
 
   void setLocation(const LayoutPoint& location) {
@@ -1311,19 +1318,41 @@ class CORE_EXPORT LayoutBox : public LayoutBoxModelObject {
 
   class MutableForPainting : public LayoutObject::MutableForPainting {
    public:
-    void setPreviousSize(const LayoutSize& size) {
-      static_cast<LayoutBox&>(m_layoutObject).m_previousSize = size;
+    void savePreviousSize() { layoutBox().m_previousSize = layoutBox().size(); }
+    void savePreviousOtherBoxGeometries() {

[mstensho (USE GERRIT), 2017/02/21 17:51:51]

Pretty unusual to inline the rareData setters. Could you move it to .cpp?

[Xianzhu, 2017/02/21 18:14:48]

Done.

+      auto& rareData = layoutBox().ensureRareData();
+      rareData.m_hasPreviousOtherBoxGeometries = true;
+      rareData.m_previousContentBoxSize = layoutBox().contentBoxRect().size();
+      rareData.m_previousLayoutOverflowRect = layoutBox().layoutOverflowRect();
+    }
+    void clearPreviousOtherBoxGeometries() {
+      if (layoutBox().m_rareData)
+        layoutBox().m_rareData->m_hasPreviousOtherBoxGeometries = false;
     }
 
    protected:
     friend class LayoutBox;
     MutableForPainting(const LayoutBox& box)
         : LayoutObject::MutableForPainting(box) {}
+    LayoutBox& layoutBox() { return static_cast<LayoutBox&>(m_layoutObject); }
   };
+
   MutableForPainting getMutableForPainting() const {
     return MutableForPainting(*this);
   }
 
+  LayoutSize previousSize() const { return m_previousSize; }
+  LayoutSize previousContentBoxSize() const {
+    return m_rareData && m_rareData->m_hasPreviousOtherBoxGeometries
+               ? m_rareData->m_previousContentBoxSize
+               : previousSize();
+  }
+  LayoutRect previousLayoutOverflowRect() const {
+    return m_rareData && m_rareData->m_hasPreviousOtherBoxGeometries
+               ? m_rareData->m_previousLayoutOverflowRect
+               : LayoutRect(LayoutPoint(), previousSize());
+  }
+
  protected:
   virtual LayoutRect controlClipRect(const LayoutPoint&) const {
     return LayoutRect();