[MediaNotification] Unset previous custom large icon correctly

chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java b/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java
index 7646bd23bee470f9f026d91e98b10fe2cd894c2d..c2f190f070d2838648b233927084598496bf1911 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java
@@ -476,10 +476,11 @@ public class MediaNotificationManager {
 
     /**
      * Scale a given bitmap to a proper size for display.
-     * @param icon The bitmap to be resized.
+     * @param icon The bitmap to be resized, can be null.
      * @return A scaled icon to be used in media notification. Returns null if |icon| is null.
      */
-    public static Bitmap scaleIconForDisplay(Bitmap icon) {
+    @Nullable
+    public static Bitmap scaleIconForDisplay(@Nullable Bitmap icon) {
         if (icon == null) return null;
 
         int largeIconSizePx = getMaximumLargeIconSize();