Add OpenXRExtendedFeatures flag

This flag allows us to configure OpenXR features which, though shipped
on Android/ARCore may not be ready to be shipped on Desktop/OpenXR, due
to the slightly different permissions, or due to an inability for us to
actually test on real hardware.

Change-Id: I985f2e17119185053539f6c2671695c57081c24f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2537584Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Reviewed-by: Klaus Weidner <klausw@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Commit-Queue: Alexander Cooper <alcooper@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827549}

content/browser/xr/service/xr_runtime_manager_impl.cc

@@ -229,9 +229,11 @@ BrowserXRRuntimeImpl* XRRuntimeManagerImpl::GetImmersiveArRuntime() {
 #endif
 
 #if BUILDFLAG(ENABLE_OPENXR)
-  auto* openxr = GetRuntime(device::mojom::XRDeviceId::OPENXR_DEVICE_ID);
-  if (openxr && openxr->SupportsArBlendMode())
-    return openxr;
+  if (base::FeatureList::IsEnabled(features::kOpenXrExtendedFeatureSupport)) {
+    auto* openxr = GetRuntime(device::mojom::XRDeviceId::OPENXR_DEVICE_ID);
+    if (openxr && openxr->SupportsArBlendMode())
+      return openxr;
+  }
 #endif
 
   return nullptr;

content/public/common/content_features.cc

@@ -438,6 +438,14 @@ const base::Feature kOriginIsolationHeader{"OriginIsolationHeader",
 const base::Feature kOriginPolicy{"OriginPolicy",
                                   base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Some WebXR features may have been enabled for ARCore, but are not yet ready
+// to be plumbed up from the OpenXR backend. This feature provides a mechanism
+// to gate such support in a generic way. Note that this feature should not be
+// used for features we intend to ship simultaneously on both OpenXR and ArCore.
+// For those features, a feature-specific flag should be created if needed.
+const base::Feature kOpenXrExtendedFeatureSupport{
+    "OpenXrExtendedFeatureSupport", base::FEATURE_DISABLED_BY_DEFAULT};
+
 // History navigation in response to horizontal overscroll (aka gesture-nav).
 const base::Feature kOverscrollHistoryNavigation {
   "OverscrollHistoryNavigation",

content/public/common/content_features.h

@@ -99,6 +99,7 @@ CONTENT_EXPORT extern const base::Feature kNotificationContentImage;
 CONTENT_EXPORT extern const base::Feature kNotificationTriggers;
 CONTENT_EXPORT extern const base::Feature kOriginIsolationHeader;
 CONTENT_EXPORT extern const base::Feature kOriginPolicy;
+CONTENT_EXPORT extern const base::Feature kOpenXrExtendedFeatureSupport;
 CONTENT_EXPORT extern const base::Feature kOverscrollHistoryNavigation;
 CONTENT_EXPORT extern const base::Feature kPeriodicBackgroundSync;
 CONTENT_EXPORT extern const base::Feature kPermissionsPolicyHeader;