[IOv2] Add support for GeometryMapper-based rect computation.

This is behind a new runtime-enabled flag called
IntersectionObserverGeometryMapper.

Bug:831762

Change-Id: I022e988d3abee45e767c04487e8e9662bfc109f2
Reviewed-on: https://chromium-review.googlesource.com/1055783
Commit-Queue: Stefan Zager <szager@chromium.org>
Reviewed-by: Stefan Zager <szager@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558143}

third_party/blink/renderer/core/frame/remote_frame_view.cc

@@ -84,8 +84,12 @@ void RemoteFrameView::UpdateViewportIntersectionsForSubtree(
   LayoutRect rect(0, 0, frame_rect_.Width(), frame_rect_.Height());
   rect.Move(remote_frame_->OwnerLayoutObject()->ContentBoxOffset());
   IntRect viewport_intersection;
+  VisualRectFlags flags =
+      RuntimeEnabledFeatures::IntersectionObserverGeometryMapperEnabled()
+          ? kUseGeometryMapper
+          : kDefaultVisualRectFlags;
   if (remote_frame_->OwnerLayoutObject()->MapToVisualRectInAncestorSpace(
-          nullptr, rect)) {
+          nullptr, rect, flags)) {
     IntRect root_visible_rect = local_root_view->VisibleContentRect();
     IntRect intersected_rect = EnclosingIntRect(rect);
     intersected_rect.Intersect(root_visible_rect);

third_party/blink/renderer/core/intersection_observer/intersection_observer_test.cc

@@ -55,9 +55,18 @@ class TestIntersectionObserverDelegate : public IntersectionObserverDelegate {
 
 }  // namespace
 
-class IntersectionObserverTest : public SimTest {};
+class IntersectionObserverTest
+    : public testing::WithParamInterface<bool>,
+      public SimTest,
+      ScopedIntersectionObserverGeometryMapperForTest {
+ public:
+  IntersectionObserverTest()
+      : ScopedIntersectionObserverGeometryMapperForTest(GetParam()) {}
+};
+
+INSTANTIATE_TEST_CASE_P(All, IntersectionObserverTest, testing::Bool());
 
-TEST_F(IntersectionObserverTest, ObserveSchedulesFrame) {
+TEST_P(IntersectionObserverTest, ObserveSchedulesFrame) {
   SimRequest main_resource("https://example.com/", "text/html");
   LoadURL("https://example.com/");
   main_resource.Complete("<div id='target'></div>");
@@ -81,7 +90,7 @@ TEST_F(IntersectionObserverTest, ObserveSchedulesFrame) {
   EXPECT_TRUE(Compositor().NeedsBeginFrame());
 }
 
-TEST_F(IntersectionObserverTest, ResumePostsTask) {
+TEST_P(IntersectionObserverTest, ResumePostsTask) {
   WebView().Resize(WebSize(800, 600));
   SimRequest main_resource("https://example.com/", "text/html");
   LoadURL("https://example.com/");
@@ -141,7 +150,7 @@ TEST_F(IntersectionObserverTest, ResumePostsTask) {
   EXPECT_EQ(observer_delegate->CallCount(), 3);
 }
 
-TEST_F(IntersectionObserverTest, DisconnectClearsNotifications) {
+TEST_P(IntersectionObserverTest, DisconnectClearsNotifications) {
   WebView().Resize(WebSize(800, 600));
   SimRequest main_resource("https://example.com/", "text/html");
   LoadURL("https://example.com/");
@@ -177,7 +186,7 @@ TEST_F(IntersectionObserverTest, DisconnectClearsNotifications) {
   EXPECT_EQ(observer_delegate->CallCount(), 1);
 }
 
-TEST_F(IntersectionObserverTest, RootIntersectionWithForceZeroLayoutHeight) {
+TEST_P(IntersectionObserverTest, RootIntersectionWithForceZeroLayoutHeight) {
   WebView().GetSettings()->SetForceZeroLayoutHeight(true);
   WebView().Resize(WebSize(800, 600));
   SimRequest main_resource("https://example.com/", "text/html");
@@ -235,7 +244,7 @@ TEST_F(IntersectionObserverTest, RootIntersectionWithForceZeroLayoutHeight) {
   EXPECT_TRUE(observer_delegate->LastIntersectionRect().IsEmpty());
 }
 
-TEST_F(IntersectionObserverTest, TrackVisibilityInit) {
+TEST_P(IntersectionObserverTest, TrackVisibilityInit) {
   ScopedIntersectionObserverV2ForTest iov2_enabled(true);
   IntersectionObserverInit observer_init;
   DummyExceptionStateForTesting exception_state;

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

@@ -116,7 +116,11 @@ void IntersectionGeometry::InitializeRootRect() {
   if (root_->IsLayoutView() &&
       !RuntimeEnabledFeatures::RootLayerScrollingEnabled()) {
     root_rect_ = LayoutRect(root_->GetFrameView()->VisibleContentRect());
-    root_->MapToVisualRectInAncestorSpace(nullptr, root_rect_);
+    root_->MapToVisualRectInAncestorSpace(
+        nullptr, root_rect_,
+        RuntimeEnabledFeatures::IntersectionObserverGeometryMapperEnabled()
+            ? kUseGeometryMapper
+            : kDefaultVisualRectFlags);
   } else if (root_->IsLayoutView() && root_->GetDocument().IsInMainFrame()) {
     // The main frame is a bit special (even after RLS) as the scrolling
     // viewport can differ in size from the LayoutView itself. There's two
@@ -160,8 +164,12 @@ void IntersectionGeometry::ClipToRoot() {
   LayoutBox* local_ancestor = nullptr;
   if (!RootIsImplicit() || root_->GetDocument().IsInMainFrame())
     local_ancestor = ToLayoutBox(root_);
+  VisualRectFlags flags = static_cast<VisualRectFlags>(
+      RuntimeEnabledFeatures::IntersectionObserverGeometryMapperEnabled()
+          ? (kUseGeometryMapper | kEdgeInclusive)
+          : kEdgeInclusive);
   does_intersect_ = target_->MapToVisualRectInAncestorSpace(
-      local_ancestor, intersection_rect_, kEdgeInclusive);
+      local_ancestor, intersection_rect_, flags);
   if (!does_intersect_ || !local_ancestor)
     return;
   if (local_ancestor->HasOverflowClip())

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -615,6 +615,9 @@
       origin_trial_feature_name: "InstalledApp",
       status: "experimental",
     },
+    {
+      name: "IntersectionObserverGeometryMapper",
+    },
     {
       name: "IntersectionObserverV2",
     },