Reland "Let SVGForeignObject's local SVG coordinates mean what it should"

third_party/WebKit/Source/core/layout/svg/LayoutSVGBlock.cpp

Index: third_party/WebKit/Source/core/layout/svg/LayoutSVGBlock.cpp
diff --git a/third_party/WebKit/Source/core/layout/svg/LayoutSVGBlock.cpp b/third_party/WebKit/Source/core/layout/svg/LayoutSVGBlock.cpp
index 452d7234e434a72b169f17fbdad3f42e98af7acc..6b93388b791d60205060d5c0cee5f84a78b921cb 100644
--- a/third_party/WebKit/Source/core/layout/svg/LayoutSVGBlock.cpp
+++ b/third_party/WebKit/Source/core/layout/svg/LayoutSVGBlock.cpp
@@ -99,6 +99,9 @@ void LayoutSVGBlock::styleDidChange(StyleDifference diff,
 void LayoutSVGBlock::mapLocalToAncestor(const LayoutBoxModelObject* ancestor,
                                         TransformState& transformState,
                                         MapCoordinatesFlags flags) const {
+  // Convert from local HTML coordinates to local SVG coordinates.
+  transformState.move(locationOffset());
+  // Apply other mappings on local SVG coordinates.
   SVGLayoutSupport::mapLocalToAncestor(this, ancestor, transformState, flags);
 }
 
@@ -108,12 +111,18 @@ void LayoutSVGBlock::mapAncestorToLocal(const LayoutBoxModelObject* ancestor,
   if (this == ancestor)
     return;
 
+  // Map to local SVG coordinates.
   SVGLayoutSupport::mapAncestorToLocal(*this, ancestor, transformState, flags);
+  // Convert from local SVG coordinates to local HTML coordinates.
+  transformState.move(locationOffset());

[Xianzhu, 2017/03/28 17:45:09]

This is the fix. In the original patch, this was "-locationOffset()". The
TransformState is already in UnapplyInverseTransformDirection mode for
mapAncestorToLocal(), so we should just apply transforms and offsets in the
normal direction.

 }
 
 const LayoutObject* LayoutSVGBlock::pushMappingToContainer(
     const LayoutBoxModelObject* ancestorToStopAt,
     LayoutGeometryMap& geometryMap) const {
+  // Convert from local HTML coordinates to local SVG coordinates.
+  geometryMap.push(this, locationOffset());
+  // Apply other mappings on local SVG coordinates.
   return SVGLayoutSupport::pushMappingToContainer(this, ancestorToStopAt,
                                                   geometryMap);
 }
@@ -128,6 +137,9 @@ bool LayoutSVGBlock::mapToVisualRectInAncestorSpaceInternal(
     VisualRectFlags) const {
   transformState.flatten();
   LayoutRect rect(transformState.lastPlanarQuad().boundingBox());
+  // Convert from local HTML coordinates to local SVG coordinates.
+  rect.moveBy(location());
+  // Apply other mappings on local SVG coordinates.
   bool retval = SVGLayoutSupport::mapToVisualRectInAncestorSpace(
       *this, ancestor, FloatRect(rect), rect);
   transformState.setQuad(FloatQuad(FloatRect(rect)));