Revert of Removed duplicated JS hasVideoInputDeviceOnSystem() test helper

content/test/data/media/webrtc_test_utilities.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // These must match with how the video and canvas tags are declared in html.
 const VIDEO_TAG_WIDTH = 320;
 const VIDEO_TAG_HEIGHT = 240;
 
 // Fake video capture background green is of value 135.
 const COLOR_BACKGROUND_GREEN = 135;
@@ skipping 245 matching lines @@
     failTest("expected '" + expected + "', got '" + actual + "'.");
   }
 }
 
 function assertTrue(booleanExpression, description) {
   if (!booleanExpression) {
     failTest(description);
   }
 }
 
+// Returns has-video-input-device to the test if there's a webcam available on
+// the system.
+function hasVideoInputDeviceOnSystem() {
+  MediaStreamTrack.getSources(function(devices) {
+    var hasVideoInputDevice = false;
+    devices.forEach(function(device) {
+      if (device.kind == 'video')
+        hasVideoInputDevice = true;
+    });
+
+    if (hasVideoInputDevice)
+      sendValueToTest('has-video-input-device');
+    else
+      sendValueToTest('no-video-input-devices');
+  });
+}