Only update media icon when necessary (#24324)

* Only update media icon when necessary

* Lint

* Comment

homeassistant/components/webostv/media_player.py

@@ -167,6 +167,7 @@ class LgWebOSDevice(MediaPlayerDevice):
         self._source_list = {}
         self._app_list = {}
         self._channel = None
+        self._last_icon = None
 
     @util.Throttle(MIN_TIME_BETWEEN_SCANS, MIN_TIME_BETWEEN_FORCED_SCANS)
     def update(self):
@@ -271,6 +272,13 @@ class LgWebOSDevice(MediaPlayerDevice):
             icon = self._app_list[self._current_source_id]['largeIcon']
             if not icon.startswith('http'):
                 icon = self._app_list[self._current_source_id]['icon']
+
+            # 'icon' holds a URL with a transient key. Avoid unnecessary
+            # updates by returning the same URL until the image changes.
+            if self._last_icon and \
+                    (icon.split('/')[-1] == self._last_icon.split('/')[-1]):
+                return self._last_icon
+            self._last_icon = icon
             return icon
         return None