[SPv175] Fix hittesting of <foreignObject> under non-identity SVG-rel…

…ated transform

If the SVG to border box transform or any other transform in SVG above <foreignObject>
is non-identity, then hit testing of the <foreignObject> and content below it is incorrect,
because it does not take into account such transforms.

Before SPv175 + <foreignObject> as stacking context, content underneath the
<foreignObject> did not paint with the correct sizing either, which hid this bug to
some extent.

To make this work requires a little bit of special-casing of foreignObject, because of
the quirk that its location offset is applied *after* transform, not before.

Bug: 820482,831591
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: Ided2b46f2ea12dd61c254892f5fbabb821f6229e
Reviewed-on: https://chromium-review.googlesource.com/974568
Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550825}

third_party/WebKit/LayoutTests/flag-specific/enable-slimming-paint-v2/paint/invalidation/svg/transform-foreign-object-expected.txt

@@ -9,12 +9,12 @@
         {
           "object": "LayoutSVGForeignObject foreignObject",
           "rect": [108, 8, 100, 100],
-          "reason": "appeared"
+          "reason": "paint property change"
         },
         {
           "object": "LayoutSVGForeignObject foreignObject",
           "rect": [8, 8, 100, 100],
-          "reason": "disappeared"
+          "reason": "paint property change"
         }
       ]
     }

third_party/WebKit/LayoutTests/paint/invalidation/svg/transform-foreign-object-expected.txt

@@ -20,12 +20,12 @@
         {
           "object": "LayoutSVGForeignObject foreignObject",
           "rect": [108, 8, 100, 100],
-          "reason": "appeared"
+          "reason": "paint property change"
         },
         {
           "object": "LayoutSVGForeignObject foreignObject",
           "rect": [8, 8, 100, 100],
-          "reason": "disappeared"
+          "reason": "paint property change"
         }
       ]
     }

third_party/blink/renderer/core/layout/layout_object.cc

@@ -2598,6 +2598,14 @@ void LayoutObject::GetTransformFromContainer(
   if (layer && layer->Transform())
     transform.Multiply(layer->CurrentTransform());
 
+  GetTransformFromContainerInternal(container_object, offset_in_container,
+                                    transform);
+}
+
+void LayoutObject::GetTransformFromContainerInternal(
+    const LayoutObject* container_object,
+    const LayoutSize& offset_in_container,
+    TransformationMatrix& transform) const {
   transform.PostTranslate(offset_in_container.Width().ToFloat(),
                           offset_in_container.Height().ToFloat());
 

third_party/blink/renderer/core/layout/layout_object.h

@@ -1621,10 +1621,11 @@ class CORE_EXPORT LayoutObject : public ImageResourceObserver,
       const LayoutBoxModelObject* ancestor_to_stop_at,
       LayoutGeometryMap&) const;
 
-  bool ShouldUseTransformFromContainer(const LayoutObject* container) const;
-  void GetTransformFromContainer(const LayoutObject* container,
-                                 const LayoutSize& offset_in_container,
-                                 TransformationMatrix&) const;
+  virtual bool ShouldUseTransformFromContainer(
+      const LayoutObject* container) const;
+  virtual void GetTransformFromContainer(const LayoutObject* container,
+                                         const LayoutSize& offset_in_container,
+                                         TransformationMatrix&) const;
 
   bool CreatesGroup() const {
     return IsTransparent() || HasMask() || HasClipPath() ||
@@ -2054,6 +2055,10 @@ class CORE_EXPORT LayoutObject : public ImageResourceObserver,
   // changes at all).
   virtual bool AnonymousHasStylePropagationOverride() { return false; }
 
+  void GetTransformFromContainerInternal(const LayoutObject* container,
+                                         const LayoutSize& offset_in_container,
+                                         TransformationMatrix&) const;
+
   // A fast path for MapToVisualRectInAncestorSpace for when GeometryMapper
   // can be used.
   bool MapToVisualRectInAncestorSpaceInternalFastPath(

third_party/blink/renderer/core/layout/svg/layout_svg_container.cc

@@ -25,6 +25,7 @@
 
 #include "third_party/blink/renderer/core/layout/hit_test_result.h"
 #include "third_party/blink/renderer/core/layout/layout_analyzer.h"
+#include "third_party/blink/renderer/core/layout/layout_box_model_object.h"
 #include "third_party/blink/renderer/core/layout/svg/svg_layout_support.h"
 #include "third_party/blink/renderer/core/layout/svg/svg_resources.h"
 #include "third_party/blink/renderer/core/layout/svg/svg_resources_cache.h"
@@ -191,6 +192,9 @@ bool LayoutSVGContainer::NodeAtFloatPoint(HitTestResult& result,
 
   for (LayoutObject* child = LastChild(); child;
        child = child->PreviousSibling()) {
+    if (child->IsBoxModelObject() &&
+        ToLayoutBoxModelObject(child)->HasSelfPaintingLayer())
+      continue;
     if (child->NodeAtFloatPoint(result, local_point, hit_test_action)) {
       const LayoutPoint& local_layout_point = LayoutPoint(local_point);
       UpdateHitTestResult(result, local_layout_point);

third_party/blink/renderer/core/layout/svg/layout_svg_foreign_object.cc

@@ -127,10 +127,10 @@ void LayoutSVGForeignObject::UpdateLayout() {
 bool LayoutSVGForeignObject::NodeAtFloatPoint(HitTestResult& result,
                                               const FloatPoint& point_in_parent,
                                               HitTestAction hit_test_action) {
-  // Embedded content is drawn in the foreground phase.
-  if (hit_test_action != kHitTestForeground)
+  if (RuntimeEnabledFeatures::SlimmingPaintV175Enabled()) {
+    NOTREACHED();
     return false;
-
+  }
   AffineTransform local_transform = LocalSVGTransform();
   if (!local_transform.IsInvertible())
     return false;
@@ -152,14 +152,24 @@ bool LayoutSVGForeignObject::NodeAtFloatPoint(HitTestResult& result,
                                   kHitTestChildBlockBackgrounds);
 }
 
+void LayoutSVGForeignObject::GetTransformFromContainer(
+    const LayoutObject* container,
+    const LayoutSize& offset_in_container,
+    TransformationMatrix& matrix) const {
+  AffineTransform to_svg_root_transform;
+  SVGLayoutSupport::ComputeTransformToSVGRoot(*this, to_svg_root_transform);
+  matrix = to_svg_root_transform;
+  GetTransformFromContainerInternal(container, offset_in_container, matrix);
+}
+
 bool LayoutSVGForeignObject::NodeAtPoint(
     HitTestResult& result,
     const HitTestLocation& location_in_parent,
     const LayoutPoint& accumulated_offset,
     HitTestAction hit_test_action) {
   if (RuntimeEnabledFeatures::SlimmingPaintV175Enabled()) {
-    return NodeAtFloatPoint(result, FloatPoint(accumulated_offset),
-                            hit_test_action);
+    return LayoutBlock::NodeAtPoint(result, location_in_parent,
+                                    accumulated_offset, hit_test_action);
   }
   NOTREACHED();
   return false;

third_party/blink/renderer/core/layout/svg/layout_svg_foreign_object.h

@@ -60,6 +60,14 @@ class LayoutSVGForeignObject final : public LayoutSVGBlock {
     return ObjectBoundingBox();
   }
 
+  bool ShouldUseTransformFromContainer(
+      const LayoutObject* container) const override {
+    return true;
+  }
+  void GetTransformFromContainer(const LayoutObject* container,
+                                 const LayoutSize& offset_in_container,
+                                 TransformationMatrix&) const override;
+
   bool NodeAtPoint(HitTestResult&,
                    const HitTestLocation&,
                    const LayoutPoint&,

third_party/blink/renderer/core/layout/svg/layout_svg_foreign_object_test.cc

@@ -34,6 +34,7 @@ TEST_F(LayoutSVGForeignObjectTest, DivInForeignObject) {
   )HTML");
 
   const auto& svg = *GetDocument().getElementById("svg");
+  const auto& foreign = *GetDocument().getElementById("foreign");
   const auto& foreign_object = *GetLayoutObjectByElementId("foreign");
   const auto& div = *GetLayoutObjectByElementId("div");
 
@@ -69,10 +70,12 @@ TEST_F(LayoutSVGForeignObjectTest, DivInForeignObject) {
             rgm.MapToAncestor(FloatRect(0, 0, 1, 2), nullptr));
 
   // Hit testing
-  EXPECT_EQ(svg, HitTest(149, 149));
+  EXPECT_EQ(svg, HitTest(1, 1));
+  EXPECT_EQ(foreign, HitTest(149, 149));
   EXPECT_EQ(div.GetNode(), HitTest(150, 150));
   EXPECT_EQ(div.GetNode(), HitTest(349, 249));
-  EXPECT_EQ(svg, HitTest(350, 250));
+  EXPECT_EQ(foreign, HitTest(350, 250));
+  EXPECT_EQ(svg, HitTest(450, 350));
 }
 
 TEST_F(LayoutSVGForeignObjectTest, IframeInForeignObject) {
@@ -95,6 +98,7 @@ TEST_F(LayoutSVGForeignObjectTest, IframeInForeignObject) {
   GetDocument().View()->UpdateAllLifecyclePhases();
 
   const auto& svg = *GetDocument().getElementById("svg");
+  const auto& foreign = *GetDocument().getElementById("foreign");
   const auto& foreign_object = *GetLayoutObjectByElementId("foreign");
   const auto& div = *ChildDocument().getElementById("div")->GetLayoutObject();
 
@@ -130,14 +134,99 @@ TEST_F(LayoutSVGForeignObjectTest, IframeInForeignObject) {
             rgm.MapToAncestor(FloatRect(0, 0, 1, 2), nullptr));
 
   // Hit testing
-  EXPECT_EQ(svg, HitTest(129, 129));
+  EXPECT_EQ(svg, HitTest(90, 90));
+  EXPECT_EQ(foreign, HitTest(129, 129));
   EXPECT_EQ(ChildDocument().documentElement(), HitTest(130, 130));
   EXPECT_EQ(ChildDocument().documentElement(), HitTest(199, 199));
   EXPECT_EQ(div.GetNode(), HitTest(200, 200));
   EXPECT_EQ(div.GetNode(), HitTest(299, 249));
   EXPECT_EQ(ChildDocument().documentElement(), HitTest(300, 250));
   EXPECT_EQ(ChildDocument().documentElement(), HitTest(369, 319));
-  EXPECT_EQ(svg, HitTest(370, 320));
+  EXPECT_EQ(foreign, HitTest(370, 320));
+  EXPECT_EQ(svg, HitTest(450, 400));
+}
+
+TEST_F(LayoutSVGForeignObjectTest, HitTestZoomedForeignObject) {
+  SetBodyInnerHTML(R"HTML(
+    <style>* { margin: 0; zoom: 150% }</style>
+    <svg id='svg' style='width: 200px; height: 200px'>
+      <foreignObject id='foreign' x='10' y='10' width='100' height='150'>
+        <div id='div' style='margin: 50px; width: 50px; height: 50px'>
+        </div>
+      </foreignObject>
+    </svg>
+  )HTML");
+
+  const auto& svg = *GetDocument().getElementById("svg");
+  const auto& foreign = *GetDocument().getElementById("foreign");
+  const auto& foreign_object = *GetLayoutObjectByElementId("foreign");
+  const auto& div = *GetDocument().getElementById("div");
+
+  EXPECT_EQ(FloatRect(10, 10, 100, 150), foreign_object.ObjectBoundingBox());
+  EXPECT_EQ(AffineTransform(), foreign_object.LocalSVGTransform());
+  EXPECT_EQ(AffineTransform(), foreign_object.LocalToSVGParentTransform());
+
+  // mapToVisualRectInAncestorSpace
+  LayoutRect div_rect(0, 0, 100, 50);
+  EXPECT_TRUE(div.GetLayoutObject()->MapToVisualRectInAncestorSpace(
+      &GetLayoutView(), div_rect));
+  EXPECT_EQ(LayoutRect(286, 286, 339, 170), div_rect);
+
+  // mapLocalToAncestor
+  TransformState transform_state(TransformState::kApplyTransformDirection,
+                                 FloatPoint());
+  div.GetLayoutObject()->MapLocalToAncestor(&GetLayoutView(), transform_state,
+                                            kTraverseDocumentBoundaries);
+  transform_state.Flatten();
+  EXPECT_EQ(FloatPoint(286.875, 286.875), transform_state.LastPlanarPoint());
+
+  // mapAncestorToLocal
+  TransformState transform_state1(
+      TransformState::kUnapplyInverseTransformDirection,
+      FloatPoint(286.875, 286.875));
+  div.GetLayoutObject()->MapAncestorToLocal(&GetLayoutView(), transform_state1,
+                                            kTraverseDocumentBoundaries);
+  transform_state1.Flatten();
+  EXPECT_EQ(FloatPoint(), transform_state1.LastPlanarPoint());
+
+  EXPECT_EQ(svg, HitTest(20, 20));
+  EXPECT_EQ(foreign, HitTest(280, 280));
+  EXPECT_EQ(div, HitTest(290, 290));
+}
+
+TEST_F(LayoutSVGForeignObjectTest, HitTestViewBoxForeignObject) {
+  SetBodyInnerHTML(R"HTML(
+    <svg id='svg' style='width: 200px; height: 200px' viewBox='0 0 100 100'>
+      <foreignObject id='foreign' x='10' y='10' width='100' height='150'>
+        <div id='div' style='margin: 50px; width: 50px; height: 50px'>
+        </div>
+      </foreignObject>
+    </svg>
+  )HTML");
+
+  const auto& svg = *GetDocument().getElementById("svg");
+  const auto& foreign = *GetDocument().getElementById("foreign");
+  const auto& div = *GetDocument().getElementById("div");
+
+  // mapLocalToAncestor
+  TransformState transform_state(TransformState::kApplyTransformDirection,
+                                 FloatPoint());
+  div.GetLayoutObject()->MapLocalToAncestor(&GetLayoutView(), transform_state,
+                                            kTraverseDocumentBoundaries);
+  transform_state.Flatten();
+  EXPECT_EQ(FloatPoint(128, 128), transform_state.LastPlanarPoint());
+
+  // mapAncestorToLocal
+  TransformState transform_state1(
+      TransformState::kUnapplyInverseTransformDirection, FloatPoint(128, 128));
+  div.GetLayoutObject()->MapAncestorToLocal(&GetLayoutView(), transform_state1,
+                                            kTraverseDocumentBoundaries);
+  transform_state1.Flatten();
+  EXPECT_EQ(FloatPoint(), transform_state1.LastPlanarPoint());
+
+  EXPECT_EQ(svg, HitTest(20, 20));
+  EXPECT_EQ(foreign, HitTest(120, 110));
+  EXPECT_EQ(div, HitTest(160, 160));
 }
 
 }  // namespace blink

third_party/blink/renderer/core/layout/svg/layout_svg_resource_clipper.cc

@@ -24,6 +24,7 @@
 
 #include "third_party/blink/renderer/core/dom/element_traversal.h"
 #include "third_party/blink/renderer/core/layout/hit_test_result.h"
+#include "third_party/blink/renderer/core/layout/layout_box_model_object.h"
 #include "third_party/blink/renderer/core/layout/svg/svg_layout_support.h"
 #include "third_party/blink/renderer/core/paint/paint_info.h"
 #include "third_party/blink/renderer/core/svg/svg_geometry_element.h"
@@ -243,6 +244,11 @@ bool LayoutSVGResourceClipper::HitTestClipContent(
     IntPoint hit_point;
     HitTestResult result(HitTestRequest::kSVGClipContent, hit_point);
     LayoutObject* layout_object = child_element.GetLayoutObject();
+
+    if (layout_object->IsBoxModelObject() &&
+        ToLayoutBoxModelObject(layout_object)->HasSelfPaintingLayer())
+      continue;
+
     if (layout_object->NodeAtFloatPoint(result, point, kHitTestForeground))
       return true;
   }

third_party/blink/renderer/core/layout/svg/layout_svg_root.cc

@@ -513,6 +513,9 @@ bool LayoutSVGRoot::NodeAtPoint(HitTestResult& result,
 
       for (LayoutObject* child = LastChild(); child;
            child = child->PreviousSibling()) {
+        if (child->IsBoxModelObject() &&
+            ToLayoutBoxModelObject(child)->HasSelfPaintingLayer())
+          continue;
         // FIXME: nodeAtFloatPoint() doesn't handle rect-based hit tests yet.
         if (child->NodeAtFloatPoint(result, local_point, hit_test_action)) {
           UpdateHitTestResult(result, point_in_border_box);

third_party/blink/renderer/core/layout/svg/svg_layout_support.cc

@@ -94,7 +94,7 @@ LayoutRect SVGLayoutSupport::TransformVisualRect(
   return LayoutRect(EnclosingIntRect(adjusted_rect));
 }
 
-static const LayoutSVGRoot& ComputeTransformToSVGRoot(
+const LayoutSVGRoot& SVGLayoutSupport::ComputeTransformToSVGRoot(
     const LayoutObject& object,
     AffineTransform& root_border_box_transform) {
   DCHECK(object.IsSVGChild());

third_party/blink/renderer/core/layout/svg/svg_layout_support.h

@@ -153,6 +153,10 @@ class CORE_EXPORT SVGLayoutSupport {
   static LayoutObject* FindClosestLayoutSVGText(const LayoutObject*,
                                                 const FloatPoint&);
 
+  static const LayoutSVGRoot& ComputeTransformToSVGRoot(
+      const LayoutObject& object,
+      AffineTransform& root_border_box_transform);
+
  private:
   static void UpdateObjectBoundingBox(FloatRect& object_bounding_box,
                                       bool& object_bounding_box_valid,