Implement PermissionService::GetNextPermissionChange.

android_webview/browser/aw_permission_manager.h

Index: android_webview/browser/aw_permission_manager.h
diff --git a/android_webview/browser/aw_permission_manager.h b/android_webview/browser/aw_permission_manager.h
index 9b7480e69e7575cd74c97c9a7d8e5b4e62367c3a..8028341fbc0ce5e3e3dae95bc6b9d0e7985ec7ee 100644
--- a/android_webview/browser/aw_permission_manager.h
+++ b/android_webview/browser/aw_permission_manager.h
@@ -38,6 +38,12 @@ class AwPermissionManager : public content::PermissionManager {
   void RegisterPermissionUsage(content::PermissionType permission,
                                const GURL& requesting_origin,
                                const GURL& embedding_origin) override;
+  int SubscribePermissionStatusChange(
+      content::PermissionType permission,
+      const GURL& requesting_origin,
+      const GURL& embedding_origin,
+      const base::Callback<void(content::PermissionStatus)>& callback) override;
+  void UnsubscribePermissionStatusChange(int subscription_id) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AwPermissionManager);