Files.app: Prevent a scroolbar from overshooting the border of the view.

chrome/browser/resources/file_manager/js/scrollbar.js

Index: chrome/browser/resources/file_manager/js/scrollbar.js
diff --git a/chrome/browser/resources/file_manager/js/scrollbar.js b/chrome/browser/resources/file_manager/js/scrollbar.js
index f20e7d9674d77afe0c460d23280b47ac21fad445..4094f44041fb930c3141fccbdca918d377e588bf 100644
--- a/chrome/browser/resources/file_manager/js/scrollbar.js
+++ b/chrome/browser/resources/file_manager/js/scrollbar.js
@@ -152,6 +152,9 @@ ScrollBar.prototype.onMouseMove_ = function(event) {
 
   var buttonPosition = this.buttonPressedPosition_ +
       (event.screenY - this.buttonPressedEvent_.screenY);
+  // Ensures the scrollbar is in the view.
+  buttonPosition =
+      Math.max(0, Math.min(buttonPosition, clientSize - buttonSize));
   var scrollPosition = totalSize * (buttonPosition / clientSize);
 
   this.scrollTop_ = scrollPosition;