Configure WebXrPermissionsApi to launch via finch

WebXrPermissionsApi is still targeting a launch in 83; however given the
current state of affairs, this switches it to be launched as a "soft
launch" via finch, so that it can easily be disabled if approval to
launch is denied at a late stage.

Change-Id: I2ada82e5649fcdb9526a07363bb15ddfd2c32b90
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2122608Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Alexander Cooper <alcooper@chromium.org>
Cr-Commit-Position: refs/heads/master@{#754613}

content/public/common/content_features.cc

@@ -814,7 +814,7 @@ const base::Feature kWebXrHitTest{"WebXRHitTest",
 const base::Feature kWebXrIncubations{"WebXRIncubations",
                                       base::FEATURE_DISABLED_BY_DEFAULT};
 const base::Feature kWebXrPermissionsApi{"WebXrPermissionsApi",
-                                         base::FEATURE_ENABLED_BY_DEFAULT};
+                                         base::FEATURE_DISABLED_BY_DEFAULT};
 
 #if defined(OS_ANDROID)
 // Autofill Accessibility in Android.

testing/variations/fieldtrial_testing_config.json

@@ -6840,6 +6840,22 @@
             ]
         }
     ],
+    "WebXrPermissionsApi": [
+        {
+            "platforms": [
+                "android",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "WebXrPermissionsApi"
+                    ]
+                }
+            ]
+        }
+    ],
     "WindowsHybridSpellCheck": [
         {
             "platforms": [