Don't cache subsequence whose layer is not fully contained by repaint rect

Source/core/frame/FrameView.h

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
@@ skipping 208 matching lines @@
     void setIsPainting(bool val) { m_isPainting = val; }
     bool isPainting() const;
     void setLastPaintTime(double val) { m_lastPaintTime = val; }
     bool hasEverPainted() const { return m_lastPaintTime; }
     void setNodeToDraw(Node*);
     Node* nodeToDraw() { return m_nodeToDraw.get(); }
 
     Color documentBackgroundColor() const;
 
     // Run all needed lifecycle stages. After calling this method, all frames will be in the lifecycle state PaintInvalidationClean.
-    void updateAllLifecyclePhases();
+    // TODO(pdr): Update callers to pass in the interest rect.
+    void updateAllLifecyclePhases(const LayoutRect& interestRect = LayoutRect::infiniteRect());
 
     // Computes the style, layout and compositing lifecycle stages if needed. After calling this method, all frames wil lbe in a lifecycle
     // state >= CompositingClean, and scrolling has been updated.
     void updateLifecycleToCompositingCleanPlusScrolling();
 
     bool invalidateViewportConstrainedObjects();
 
     void incrementVisuallyNonEmptyCharacterCount(unsigned);
     void incrementVisuallyNonEmptyPixelCount(const IntSize&);
     bool isVisuallyNonEmpty() const { return m_isVisuallyNonEmpty; }
@@ skipping 365 matching lines @@
     explicit FrameView(LocalFrame*);
 
     void setScrollOffset(const IntPoint&, ScrollType) override;
     void setScrollOffset(const DoublePoint&, ScrollType) override;
 
     enum LifeCycleUpdateOption {
         AllPhases,
         OnlyUpToCompositingCleanPlusScrolling,
     };
 
-    void updateLifecyclePhasesInternal(LifeCycleUpdateOption);
+    void updateLifecyclePhasesInternal(LifeCycleUpdateOption, const LayoutRect& interestRect = LayoutRect::infiniteRect());
     void invalidateTreeIfNeededRecursive();
     void scrollContentsIfNeededRecursive();
     void updateStyleAndLayoutIfNeededRecursive();
-    void paintForSlimmingPaintV2();
+    void paintForSlimmingPaintV2(const LayoutRect& interestRect);
     void compositeForSlimmingPaintV2();
 
     void reset();
     void init();
 
     void clearLayoutSubtreeRootsAndMarkContainingBlocks();
 
     // Called when our frame rect changes (or the rect/scroll position of an ancestor changes).
     void frameRectsChanged() override;
 
@@ skipping 232 matching lines @@
     static const unsigned visualPixelThreshold = 32 * 32;
     if (m_visuallyNonEmptyPixelCount > visualPixelThreshold)
         setIsVisuallyNonEmpty();
 }
 
 DEFINE_TYPE_CASTS(FrameView, Widget, widget, widget->isFrameView(), widget.isFrameView());
 
 } // namespace blink
 
 #endif // FrameView_h