DevTools: Allow tab key to move focus when ConsolePrompt is empty

third_party/WebKit/Source/devtools/front_end/console/ConsolePrompt.js

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 /**
  * @unrestricted
  */
 Console.ConsolePrompt = class extends UI.Widget {
   constructor() {
     super();
     this._addCompletionsFromHistory = true;
@@ skipping 114 matching lines @@
         }
         break;
       case UI.KeyboardShortcut.Keys.N.code:  // Ctrl+N = Next
         if (Host.isMac() && keyboardEvent.ctrlKey && !keyboardEvent.metaKey && !keyboardEvent.altKey &&
             !keyboardEvent.shiftKey)
           newText = this._history.next();
         break;
       case UI.KeyboardShortcut.Keys.Enter.code:
         this._enterKeyPressed(keyboardEvent);
         break;
+      case UI.KeyboardShortcut.Keys.Tab.code:
+        if (!this.text())
+          keyboardEvent.consume();
+        break;
     }
 
     if (newText === undefined)
       return;
     keyboardEvent.consume(true);
     this.setText(newText);
 
     if (isPrevious)
       this._editor.setSelection(TextUtils.TextRange.createFromLocation(0, Infinity));
     else
@@ skipping 229 matching lines @@
    * @return {string|undefined}
    */
   _currentHistoryItem() {
     return this._data[this._data.length - this._historyOffset];
   }
 };
 
 Console.ConsolePrompt.Events = {
   TextChanged: Symbol('TextChanged')
 };