Support edge-inclusive intersections in mapToVisibleRectInAncestorSpace

third_party/WebKit/Source/core/layout/LayoutView.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 457 matching lines @@
 {
     setShouldDoFullPaintInvalidation();
 
     // The only way we know how to hit these ASSERTS below this point is via the Chromium OS login screen.
     DisableCompositingQueryAsserts disabler;
 
     if (compositor()->inCompositingMode())
         compositor()->fullyInvalidatePaint();
 }
 
-void LayoutView::mapToVisibleRectInAncestorSpace(const LayoutBoxModelObject* ancestor, LayoutRect& rect, const PaintInvalidationState* invalidationState) const
+bool LayoutView::mapToVisibleRectInAncestorSpace(const LayoutBoxModelObject* ancestor, LayoutRect& rect, const PaintInvalidationState* invalidationState, int flags) const
 {
-    mapToVisibleRectInAncestorSpace(ancestor, rect, IsNotFixedPosition, invalidationState);
+    return mapToVisibleRectInAncestorSpace(ancestor, rect, IsNotFixedPosition, invalidationState, flags);
 }
 
-void LayoutView::mapToVisibleRectInAncestorSpace(const LayoutBoxModelObject* ancestor, LayoutRect& rect, ViewportConstrainedPosition viewportConstraint, const PaintInvalidationState* state) const
+bool LayoutView::mapToVisibleRectInAncestorSpace(const LayoutBoxModelObject* ancestor, LayoutRect& rect, ViewportConstrainedPosition viewportConstraint, const PaintInvalidationState* state, int flags) const
 {
     if (document().printing())
-        return;
+        return true;
 
     if (style()->isFlippedBlocksWritingMode()) {
         // We have to flip by hand since the view's logical height has not been determined.  We
         // can use the viewport width and height.
         if (style()->isHorizontalWritingMode())
             rect.setY(viewHeight() - rect.maxY());
         else
             rect.setX(viewWidth() - rect.maxX());
     }
 
     adjustViewportConstrainedOffset(rect, viewportConstraint);
 
     // Apply our transform if we have one (because of full page zooming).
     if (!ancestor && layer() && layer()->transform())
         rect = layer()->transform()->mapRect(rect);
 
     ASSERT(ancestor);
     if (ancestor == this)
-        return;
+        return true;
 
     Element* owner = document().ownerElement();
     if (!owner)
-        return;
+        return true;
 
     if (LayoutBox* obj = owner->layoutBox()) {
         if (!state || !state->viewClippingAndScrollOffsetDisabled()) {
             // Intersect the viewport with the paint invalidation rect.
             LayoutRect viewRectangle = viewRect();
-            rect.intersect(viewRectangle);
+            if (flags & EdgeInclusive) {
+                if (!rect.inclusiveIntersect(viewRectangle))
+                    return false;
+            } else {
+                rect.intersect(viewRectangle);

[chrishtr, 2016/03/22 17:25:49]

return false here if it's empty? Early out code?

+            }
 
             // Adjust for scroll offset of the view.
             rect.moveBy(-viewRectangle.location());
         }
 
         // Adjust for frame border.
         rect.move(obj->contentBoxOffset());
-        obj->mapToVisibleRectInAncestorSpace(ancestor, rect, 0);
+        return obj->mapToVisibleRectInAncestorSpace(ancestor, rect, 0, flags);
     }
+
+    return true;
 }
 
 void LayoutView::adjustViewportConstrainedOffset(LayoutRect& rect, ViewportConstrainedPosition viewportConstraint) const
 {
     if (viewportConstraint != IsFixedPosition)
         return;
 
     if (m_frameView) {
         rect.move(toIntSize(m_frameView->scrollPosition()));
         if (hasOverflowClip())
@@ skipping 492 matching lines @@
 
 ScrollResult LayoutView::scroll(ScrollGranularity granularity, const FloatSize& delta)
 {
     if (!frameView())
         return ScrollResult();
 
     return frame()->applyScrollDelta(granularity, delta, false);
 }
 
 } // namespace blink