Retire IntersectionObserverV2 runtime flag

The flag IntersectionObserverV2 has been stable since 2019-01.

Bug: 827639
Change-Id: I31e4e6b5a0cdae99a0a3c56d504a99216cc653b5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2208802Reviewed-by: Stefan Zager <szager@chromium.org>
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772052}

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

@@ -64,8 +64,7 @@ bool FrameView::UpdateViewportIntersection(unsigned flags,
   bool should_compute_occlusion =
       needs_occlusion_tracking &&
       occlusion_state == FrameOcclusionState::kGuaranteedNotOccluded &&
-      parent_lifecycle_state >= DocumentLifecycle::kPrePaintClean &&
-      RuntimeEnabledFeatures::IntersectionObserverV2Enabled();
+      parent_lifecycle_state >= DocumentLifecycle::kPrePaintClean;
 
   LayoutEmbeddedContent* owner_layout_object =
       owner_element->GetLayoutEmbeddedContent();

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

@@ -93,7 +93,6 @@ LayoutView* LocalRootView(const LayoutObject& object) {
 //
 //   https://w3c.github.io/IntersectionObserver/v2/#calculate-visibility-algo
 bool ComputeIsVisible(const LayoutObject* target, const PhysicalRect& rect) {
-  DCHECK(RuntimeEnabledFeatures::IntersectionObserverV2Enabled());
   if (target->GetDocument().GetFrame()->LocalFrameRoot().GetOcclusionState() !=
       FrameOcclusionState::kGuaranteedNotOccluded) {
     return false;

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

@@ -169,20 +169,18 @@ IntersectionObserver* IntersectionObserver::Create(
 
   DOMHighResTimeStamp delay = 0;
   bool track_visibility = false;
-  if (RuntimeEnabledFeatures::IntersectionObserverV2Enabled()) {
-    delay = observer_init->delay();
-    track_visibility = observer_init->trackVisibility();
-    if (track_visibility && delay < 100) {
-      exception_state.ThrowDOMException(
-          DOMExceptionCode::kNotSupportedError,
-          "To enable the 'trackVisibility' option, you must also use a "
-          "'delay' option with a value of at least 100. Visibility is more "
-          "expensive to compute than the basic intersection; enabling this "
-          "option may negatively affect your page's performance. Please make "
-          "sure you *really* need visibility tracking before enabling the "
-          "'trackVisibility' option.");
-      return nullptr;
-    }
+  delay = observer_init->delay();
+  track_visibility = observer_init->trackVisibility();
+  if (track_visibility && delay < 100) {
+    exception_state.ThrowDOMException(
+        DOMExceptionCode::kNotSupportedError,
+        "To enable the 'trackVisibility' option, you must also use a "
+        "'delay' option with a value of at least 100. Visibility is more "
+        "expensive to compute than the basic intersection; enabling this "
+        "option may negatively affect your page's performance. Please make "
+        "sure you *really* need visibility tracking before enabling the "
+        "'trackVisibility' option.");
+    return nullptr;
   }
 
   Vector<Length> root_margin;

third_party/blink/renderer/core/intersection_observer/intersection_observer.idl

@@ -15,8 +15,8 @@ callback IntersectionObserverCallback = void (sequence<IntersectionObserverEntry
     readonly attribute DOMString rootMargin;
     // https://github.com/WICG/IntersectionObserver/issues/114
     readonly attribute FrozenArray<double> thresholds;
-    [RuntimeEnabled=IntersectionObserverV2] readonly attribute DOMHighResTimeStamp delay;
-    [RuntimeEnabled=IntersectionObserverV2] readonly attribute boolean trackVisibility;
+    readonly attribute DOMHighResTimeStamp delay;
+    readonly attribute boolean trackVisibility;
     [RaisesException] void observe(Element target);
     [RaisesException] void unobserve(Element target);
     [RaisesException] void disconnect();

third_party/blink/renderer/core/intersection_observer/intersection_observer_entry.idl

@@ -13,7 +13,7 @@
     readonly attribute DOMRectReadOnly boundingClientRect;
     readonly attribute DOMRectReadOnly intersectionRect;
     readonly attribute boolean isIntersecting;
-    [RuntimeEnabled=IntersectionObserverV2] readonly attribute boolean isVisible;
+    readonly attribute boolean isVisible;
     readonly attribute double intersectionRatio;
     readonly attribute Element target;
 };

third_party/blink/renderer/core/intersection_observer/intersection_observer_init.idl

@@ -8,6 +8,6 @@ dictionary IntersectionObserverInit {
     (Element or Document)? root = null;
     DOMString rootMargin = "0px";
     (double or sequence<double>) threshold = 0;
-    [RuntimeEnabled=IntersectionObserverV2] DOMHighResTimeStamp delay = 0;
-    [RuntimeEnabled=IntersectionObserverV2] boolean trackVisibility = false;
+    DOMHighResTimeStamp delay = 0;
+    boolean trackVisibility = false;
 };

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

@@ -80,11 +80,9 @@ class TestIntersectionObserverDelegate : public IntersectionObserverDelegate {
 
 class IntersectionObserverTest : public SimTest {};
 
-class IntersectionObserverV2Test : public IntersectionObserverTest,
-                                   public ScopedIntersectionObserverV2ForTest {
+class IntersectionObserverV2Test : public IntersectionObserverTest {
  public:
-  IntersectionObserverV2Test()
-      : IntersectionObserverTest(), ScopedIntersectionObserverV2ForTest(true) {
+  IntersectionObserverV2Test() {
     IntersectionObserver::SetThrottleDelayEnabledForTesting(false);
   }
 

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -899,10 +899,6 @@
       name: "IntersectionObserverDocumentScrollingElementRoot",
       status: "stable",
     },
-    {
-      name: "IntersectionObserverV2",
-      status: "stable",
-    },
     {
       // Launched by default. TODO(mythria): cleanup virtual tests and
       // other hooks in blink.