Add UseCounters for hit test (both API variants) and for DOM overlay

Bug: 1054952
Change-Id: Ic03ce2e03fc8c6e55e5cc46faf49057f32593404
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2070966
Commit-Queue: Piotr Bialecki <bialpio@chromium.org>
Commit-Queue: Klaus Weidner <klausw@chromium.org>
Auto-Submit: Piotr Bialecki <bialpio@chromium.org>
Reviewed-by: Klaus Weidner <klausw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#744130}

third_party/blink/public/mojom/web_feature/web_feature.mojom

@@ -2509,6 +2509,9 @@ enum WebFeature {
   kV8ArrayPrototypeHasElements = 3163,
   kV8ObjectPrototypeHasElements = 3164,
   kDisallowDocumentAccess = 3165,
+  kXRSessionRequestHitTestSource = 3166,
+  kXRSessionRequestHitTestSourceForTransientInput = 3167,
+  kXRDOMOverlay = 3168,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots.

third_party/blink/renderer/modules/xr/xr.cc

@@ -425,6 +425,8 @@ void XR::PendingRequestSessionQuery::ReportRequestSessionResult(
       XRSessionFeature::REF_SPACE_BOUNDED_FLOOR, session);
   auto feature_request_unbounded =
       GetFeatureRequestStatus(XRSessionFeature::REF_SPACE_UNBOUNDED, session);
+  auto feature_request_dom_overlay =
+      GetFeatureRequestStatus(XRSessionFeature::DOM_OVERLAY, session);
 
   ukm::builders::XR_WebXR_SessionRequest(ukm_source_id_)
       .SetMode(static_cast<int64_t>(mode_))
@@ -437,6 +439,15 @@ void XR::PendingRequestSessionQuery::ReportRequestSessionResult(
       .SetFeature_Unbounded(static_cast<int64_t>(feature_request_unbounded))
       .Record(doc->UkmRecorder());
 
+  // If the session was successfully created and DOM overlay was requested,
+  // count this as a use of the DOM overlay feature.
+  if (session && status == SessionRequestStatus::kSuccess &&
+      feature_request_dom_overlay !=
+          device::mojom::XRSessionFeatureRequestStatus::kNotRequested) {
+    UseCounter::Count(session->GetExecutionContext(),
+                      WebFeature::kXRDOMOverlay);
+  }
+
   if (session && metrics_recorder) {
     mojo::Remote<device::mojom::blink::XRSessionMetricsRecorder> recorder(
         std::move(metrics_recorder));

third_party/blink/renderer/modules/xr/xr_session.idl

@@ -58,8 +58,8 @@ enum XRVisibilityState {
   [CallWith=ScriptState, Measure, RaisesException] Promise<void> end();
 
   // https://github.com/immersive-web/hit-test/blob/master/hit-testing-explainer.md
-  [RuntimeEnabled=WebXRHitTest, CallWith=ScriptState, RaisesException]
+  [RuntimeEnabled=WebXRHitTest, CallWith=ScriptState, MeasureAs=XRSessionRequestHitTestSource, RaisesException]
   Promise<XRHitTestSource> requestHitTestSource(XRHitTestOptionsInit options);
-  [RuntimeEnabled=WebXRHitTest, CallWith=ScriptState, RaisesException]
+  [RuntimeEnabled=WebXRHitTest, CallWith=ScriptState, MeasureAs=XRSessionRequestHitTestSourceForTransientInput, RaisesException]
   Promise<XRTransientInputHitTestSource> requestHitTestSourceForTransientInput(XRTransientInputHitTestOptionsInit options);
 };

tools/metrics/histograms/enums.xml

@@ -26551,6 +26551,9 @@ to ensure that the crash string is shown properly on the user-facing crash UI.
   <int value="3163" label="V8ArrayPrototypeHasElements"/>
   <int value="3164" label="V8ObjectPrototypeHasElements"/>
   <int value="3165" label="DisallowDocumentAccess"/>
+  <int value="3166" label="XRSessionRequestHitTestSource"/>
+  <int value="3167" label="XRSessionRequestHitTestSourceForTransientInput"/>
+  <int value="3168" label="XRDOMOverlay"/>
 </enum>
 
 <enum name="FeaturePolicyAllowlistType">