Support edge-inclusive intersections in mapToVisibleRectInAncestorSpace

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 007845e72fff036449020792a49f33fb7ac9398c..fcaa9435f3b8aab4218d59f025583cfe4a21ebf2 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.h
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.h
@@ -639,7 +639,7 @@ public:
     bool hasForcedBreakAfter() const;
 
     LayoutRect clippedOverflowRectForPaintInvalidation(const LayoutBoxModelObject* paintInvalidationContainer, const PaintInvalidationState* = nullptr) const override;
-    void mapToVisibleRectInAncestorSpace(const LayoutBoxModelObject* ancestor, LayoutRect&, const PaintInvalidationState*) const override;
+    bool mapToVisibleRectInAncestorSpace(const LayoutBoxModelObject* ancestor, LayoutRect&, const PaintInvalidationState*, bool edgeInclusive) const override;

[chrishtr, 2016/03/21 22:14:50]

Upgrade this bool to a bitfield, and default it to 0.

[ojan, 2016/03/21 22:23:05]

Use an enum instead of a bool argument.

[szager1, 2016/03/22 00:55:48]

Done.

[ojan, 2016/03/22 04:24:47]

Why a bitfield instead of an enum? In my experience, the places we use bitfield
arguments often lead to hard to understand, spaghetti code.

     virtual void invalidatePaintForOverhangingFloats(bool paintAllDescendants);
 
     LayoutUnit containingBlockLogicalHeightForGetComputedStyle() const;
@@ -842,7 +842,11 @@ public:
 
     IntSize scrolledContentOffset() const;
     void mapScrollingContentsRectToBoxSpace(LayoutRect&) const;
-    void applyOverflowClip(LayoutRect&) const;
+
+    // Returns true if the rect actually intersects the clipping region.
+    // If edgeInclusive is true, then this method may return true even
+    // if the resulting rect has zero area.
+    bool applyOverflowClip(LayoutRect&, bool edgeInclusive) const;
 
     virtual bool hasRelativeLogicalWidth() const;
     virtual bool hasRelativeLogicalHeight() const;