Use getComputedStyle instead of player.width

When upswitching, we try to find the best resolution based on bandwidth
and based on the player dimensions. However, player.width will return
the set width value of the player (https://github.com/videojs/video.js/issues/2282) instead of the current value which means that in fullscreen we don't think we the player changes size and so we don't upswitch.

@@ -486,7 +486,9 @@ videojs.Hls.prototype.selectPlaylist = function () {
     oldvariant,
     bandwidthBestVariant,
     resolutionPlusOne,
-    resolutionBestVariant;
+    resolutionBestVariant,
+    playerWidth,
+    playerHeight;
 
   sortedPlaylists.sort(videojs.Hls.comparePlaylistBandwidth);
 
@@ -522,6 +524,9 @@ videojs.Hls.prototype.selectPlaylist = function () {
   // (this could be the lowest bitrate rendition as  we go through all of them above)
   variant = null;
 
+  playerWidth = parseInt(getComputedStyle(player.el()).width, 10);
+  playerHeight = parseInt(getComputedStyle(player.el()).height, 10);
+
   // iterate through the bandwidth-filtered playlists and find
   // best rendition by player dimension
   while (i--) {
@@ -539,14 +544,14 @@ videojs.Hls.prototype.selectPlaylist = function () {
 
     // since the playlists are sorted, the first variant that has
     // dimensions less than or equal to the player size is the best
-    if (variant.attributes.RESOLUTION.width === player.width() &&
-        variant.attributes.RESOLUTION.height === player.height()) {
+    if (variant.attributes.RESOLUTION.width === playerWidth &&
+        variant.attributes.RESOLUTION.height === playerHeight) {
       // if we have the exact resolution as the player use it
       resolutionPlusOne = null;
       resolutionBestVariant = variant;
       break;
-    } else if (variant.attributes.RESOLUTION.width < player.width() &&
-        variant.attributes.RESOLUTION.height < player.height()) {
+    } else if (variant.attributes.RESOLUTION.width < playerWidth &&
+        variant.attributes.RESOLUTION.height < playerHeight) {
       // if we don't have an exact match, see if we have a good higher quality variant to use
       if (oldvariant && oldvariant.attributes && oldvariant.attributes.RESOLUTION &&
           oldvariant.attributes.RESOLUTION.width && oldvariant.attributes.RESOLUTION.height) {