Fix drm detection, but hopefully for real

src/ext/lib/ar-detect/DrmDetecor.js

@@ -1,5 +1,3 @@
-import BrowserDetect from '../../conf/BrowserDetect';
-
 /**
  * Checks whether video we're trying to play is protected by DRM. 
  * @param {*} video video we're trying to check
@@ -10,47 +8,5 @@ export function hasDrm(video) {
     return undefined;
   }
 
-  /**
-   * DRM DETECTION 101:
-   *
-   * When trying to get an image frame of a DRM-protected video in
-   * firefox, the method canvas.drawImage(video) will throw an exception.
-   * 
-   * This doesn't happen in Chrome. As opposed to Firefox, chrome will
-   * simply draw a transparent black image and not tell anyone that
-   * anything is amiss. However, since the image is (according to my testing
-   * on netflix) completely transparent, this means we can determine whether
-   * the video is DRM-protected by looking at the alpha byte of the image.
-   * 
-   * (Videos don't tend to have an alpha channel, so they're always
-   * completely opaque (i.e. have value of 255))
-   */
-
-  // setup canvas
-  const canvas = document.createElement('canvas');
-  canvas.width = 2;
-  canvas.height = 2;
-  const context = canvas.getContext('2d');
-
-  if (BrowserDetect.firefox) {
-    try {
-      context.drawImage(video, 0, 0, canvas.width, canvas.height);
-      return false;
-    } catch (e) {
-      console.error('Exception occured while trying to draw image. Error:', e);
-      return true;
-    }
-  } else if (BrowserDetect.anyChromium) {
-    // oh btw, there's one exception to the alpha rule.
-    // There is this brief period between the point
-    // when metadata (video dimensions) have loaded and the moment the video starts
-    // playing where ctx.drawImage() will draw a transparent black square regardless
-    // of whether the video is actually DRM-protected or not.
-
-    context.drawImage(video, 0, 0, canvas.width, canvas.height);
-
-    console.log(context.getImageData(0,0,1,1).data, 'drm result', video.videoTracks)
-
-    return context.getImageData(0,0,1,1).data[3] === 0;
-  }
+  return video.mediaKeys instanceof MediaKeys;
 }