Remove resolved TODO

ui/file_manager/file_manager/foreground/js/ui/scrollbar.js

Index: ui/file_manager/file_manager/foreground/js/ui/scrollbar.js
diff --git a/ui/file_manager/file_manager/foreground/js/ui/scrollbar.js b/ui/file_manager/file_manager/foreground/js/ui/scrollbar.js
index a5f389869f3d1d1a00d2e6a50891558a73325fd4..d187c9630025ddd03526c2a278de54a9ade265e2 100644
--- a/ui/file_manager/file_manager/foreground/js/ui/scrollbar.js
+++ b/ui/file_manager/file_manager/foreground/js/ui/scrollbar.js
@@ -181,7 +181,6 @@ ScrollBar.prototype.onMouseMove_ = function(event) {
   }
   var clientSize = this.clientHeight_;
   var totalSize = this.scrollHeight_;
-  // TODO(hirono): Fix the geometric calculation.  crbug.com/253779
   var buttonSize = Math.max(50, clientSize / totalSize * clientSize);
   var buttonPosition = this.buttonPressedPosition_ +
       (event.screenY - this.buttonPressedEvent_.screenY);