Fix keyboard commands on bookmarks page.

chrome/browser/resources/md_downloads/crisper.js

Index: chrome/browser/resources/md_downloads/crisper.js
diff --git a/chrome/browser/resources/md_downloads/crisper.js b/chrome/browser/resources/md_downloads/crisper.js
index d0019b729dba518417f5ca5c412a310bbc8f6276..fab57c470d3cc3d2cb50beaea991ce0b79e78fa7 100644
--- a/chrome/browser/resources/md_downloads/crisper.js
+++ b/chrome/browser/resources/md_downloads/crisper.js
@@ -1699,20 +1699,6 @@ function quoteString(str) {
     'use strict';
 
     /**
-     * Chrome uses an older version of DOM Level 3 Keyboard Events

[Dan Beam, 2016/07/12 19:59:30]

this is just gonna get replaced the next time we vulcanize the downloads page. 
this is from polymer somewhere.  it'd be hard to remove it.

-     *
-     * Most keys are labeled as text, but some are Unicode codepoints.
-     * Values taken from: http://www.w3.org/TR/2007/WD-DOM-Level-3-Events-20071221/keyset.html#KeySet-Set
-     */
-    var KEY_IDENTIFIER = {
-      'U+0008': 'backspace',
-      'U+0009': 'tab',
-      'U+001B': 'esc',
-      'U+0020': 'space',
-      'U+007F': 'del'
-    };
-
-    /**
      * Special table for KeyboardEvent.keyCode.
      * KeyBoardEvent.key is even better than that.
      *