Make CaretBase a DisplayItemClient.

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
  * modify it under the terms of the GNU Library General Public
@@ skipping 1090 matching lines @@
     // different document.
     //
     // This is the container that should be passed to
     // the '*forPaintInvalidation' methods.
     const LayoutBoxModelObject& containerForPaintInvalidation() const;
 
     bool isPaintInvalidationContainer() const;
 
     // Invalidate the paint of a specific subrectangle within a given object. The rect is in the object's coordinate space.
     // If a DisplayItemClient is specified, that client is invalidated rather than |this|.
-    void invalidatePaintRectangle(const LayoutRect&, DisplayItemClient* = nullptr) const;
+    // Returns the visual rect that was invalidated (i.e, invalidation in the space of the GraphicsLayer backing this LayoutObject).
+    LayoutRect invalidatePaintRectangle(const LayoutRect&, DisplayItemClient* = nullptr) const;
 
     // Walk the tree after layout issuing paint invalidations for layoutObjects that have changed or moved, updating bounds that have changed, and clearing paint invalidation state.
     virtual void invalidateTreeIfNeeded(const PaintInvalidationState&);
 
     void setShouldDoFullPaintInvalidationIncludingNonCompositingDescendants();
 
     // Returns true if the object itself will not generate any effective painted output no matter what
     // size the object is. For example, this function can return false for an object whose size is
     // currently 0x0 but would have effective painted output if it was set a non-empty size.
     // It's used to skip unforced paint invalidation (which is when shouldDoFullPaintInvalidation
@@ skipping 1011 matching lines @@
 void showTree(const blink::LayoutObject*);
 void showLineTree(const blink::LayoutObject*);
 void showLayoutTree(const blink::LayoutObject* object1);
 // We don't make object2 an optional parameter so that showLayoutTree
 // can be called from gdb easily.
 void showLayoutTree(const blink::LayoutObject* object1, const blink::LayoutObject* object2);
 
 #endif
 
 #endif // LayoutObject_h