Add RegionCaptureExperimentalSubtypes to fieldtrial_testing_config.json

Bug: None
Change-Id: I7946edb917d81118b3421014a09ea8c0a45dcb98
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3934359
Reviewed-by: Jordan Bayles <[email protected]>
Commit-Queue: Elad Alon <[email protected]>
Auto-Submit: Elad Alon <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1055214}

mediacapture-region/CropTarget-fromElement.https.html

@@ -14,7 +14,7 @@ <h1 class="instructions">Description</h1>
 
   <div id='test-div'></div>
   <iframe id='test-iframe' src="about:blank"></iframe>
-  <a id='test-a'></a>
+  <img id='test-img' alt='Alt text' width="500" height="600">
   <div id='log'></div>
 
   <script src=/resources/testharness.js></script>
@@ -37,6 +37,15 @@ <h1 class="instructions">Description</h1>
       assert_equals(crop_target.constructor.name, 'CropTarget');
     }, "Produces a CropTarget for Elements of subtype div.");
 
+    // TODO(crbug.com/1247761): Re-enable after rolling out the
+    // experiment to allow any Element.
+    // promise_test(function (t) {
+    //   assert_true(!!CropTarget.fromElement);
+    //
+    //   return promise_rejects_dom(t, "NotSupportedError",
+    //     CropTarget.fromElement(document.getElementById("test-img")));
+    // }, "Produces a CropTarget for Elements of subtype img.");
+
     promise_test(t => {
       assert_true(!!CropTarget.fromElement);
       return promise_rejects_js(t, TypeError,
@@ -48,13 +57,6 @@ <h1 class="instructions">Description</h1>
       return promise_rejects_js(t, TypeError, CropTarget.fromElement(123));
     }, "Rejects a non-Element with a TypeError.");
 
-    promise_test(function (t) {
-      assert_true(!!CropTarget.fromElement);
-
-      return promise_rejects_dom(t, "NotSupportedError",
-        CropTarget.fromElement(document.getElementById("test-a")));
-    }, "Rejects unimplemented Element subtypes with a NotSupportedError");
-
     promise_test(async () => {
       assert_true(!!CropTarget.fromElement);