Remove unused ChromeBrowserInitializer interface

The ChromeBrowserInitializer.OnNewVersionAvailableCallback interface is
unused. Clean it up.

Change-Id: Ieeccd9d194b1fa34a8fb6b8db83bd5e79d84a2ec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1959374Reviewed-by: Gang Wu <gangwu@chromium.org>
Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
Commit-Queue: Natalie Chouinard <chouinard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#724093}

chrome/android/java/src/org/chromium/chrome/browser/init/ChromeBrowserInitializer.java

@@ -73,17 +73,6 @@ public class ChromeBrowserInitializer {
     private boolean mNativeInitializationComplete;
     private boolean mNetworkChangeNotifierInitializationComplete;
 
-    /**
-     * A callback to be executed when there is a new version available in Play Store.
-     */
-    public interface OnNewVersionAvailableCallback extends Runnable {
-        /**
-         * Set the update url to get the new version available.
-         * @param updateUrl The url to be used.
-         */
-        void setUpdateUrl(String updateUrl);
-    }
-
     /**
      * This class is an application specific object that orchestrates the app initialization.
      * @return The singleton instance of {@link ChromeBrowserInitializer}.