DevTools: [ux regression] There is no way to clear console history.

third_party/WebKit/Source/devtools/front_end/ui/TextPrompt.js

 /*
  * Copyright (C) 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2011 Google Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 453 matching lines @@
      * @return {?Range}
      * @suppressGlobalPropertiesCheck
      */
     _createRange: function()
     {
         return document.createRange();
     },
 
     /**
      * @param {string} prefix
-     * @return {!Array.<string>}
+     * @return {!Array.<{title: string, className: (string|undefined)}>}

[dgozman, 2016/03/24 18:39:34]

WebInspector.SuggestBox.Suggestions

      */
     additionalCompletions: function(prefix)
     {
         return [];
     },
 
     /**
      * @param {!Selection} selection
      * @param {!Range} originalWordPrefixRange
      * @param {boolean} reverse
      * @param {boolean} force
      * @param {!Array.<string>} completions
      * @param {number=} selectedIndex
      */
     _completionsReady: function(selection, originalWordPrefixRange, reverse, force, completions, selectedIndex)
     {
         var prefix = originalWordPrefixRange.toString();
-        if (prefix || force) {
-            if (prefix)
-                completions = completions.concat(this.additionalCompletions(prefix));
-            else
-                completions = this.additionalCompletions(prefix).concat(completions);
-        }
 
         // Filter out dupes.
         var store = new Set();
         completions = completions.filter(item => !store.has(item) && !!store.add(item));
+        var annotatedCompletions = completions.map(item => ({title: item}));
 
-        if (!this._waitingForCompletions || !completions.length) {
+        if (prefix || force) {
+            if (prefix)
+                annotatedCompletions = annotatedCompletions.concat(this.additionalCompletions(prefix));
+            else
+                annotatedCompletions = this.additionalCompletions(prefix).concat(annotatedCompletions);
+        }
+
+        if (!this._waitingForCompletions || !annotatedCompletions.length) {
             this.hideSuggestBox();
             return;
         }
 
         delete this._waitingForCompletions;
 
         var selectionRange = selection.getRangeAt(0);
 
         var fullWordRange = this._createRange();
         fullWordRange.setStart(originalWordPrefixRange.startContainer, originalWordPrefixRange.startOffset);
         fullWordRange.setEnd(selectionRange.endContainer, selectionRange.endOffset);
 
         if (prefix + selectionRange.toString() !== fullWordRange.toString())
             return;
 
         selectedIndex = (this._disableDefaultSuggestionForEmptyInput && !this.text()) ? -1 : (selectedIndex || 0);
 
         this._userEnteredRange = fullWordRange;
         this._userEnteredText = fullWordRange.toString();
 
         if (this._suggestBox)
-            this._suggestBox.updateSuggestions(this._boxForAnchorAtStart(selection, fullWordRange), completions, selectedIndex, !this.isCaretAtEndOfPrompt(), this._userEnteredText);
+            this._suggestBox.updateSuggestions(this._boxForAnchorAtStart(selection, fullWordRange), annotatedCompletions, selectedIndex, !this.isCaretAtEndOfPrompt(), this._userEnteredText);
 
         if (selectedIndex === -1)
             return;
 
         var wordPrefixLength = originalWordPrefixRange.toString().length;
         this._commonPrefix = this._buildCommonPrefix(completions, wordPrefixLength);
 
         if (this.isCaretAtEndOfPrompt()) {
-            var completionText = completions[selectedIndex];
+            var completionText = annotatedCompletions[selectedIndex].title;
             var prefixText = this._userEnteredRange.toString();
             var suffixText = completionText.substring(wordPrefixLength);
             this._userEnteredRange.deleteContents();
             this._element.normalize();
             var finalSelectionRange = this._createRange();
 
             var prefixTextNode = createTextNode(prefixText);
             fullWordRange.insertNode(prefixTextNode);
 
             this.autoCompleteElement = createElementWithClass("span", "auto-complete-text");
@@ skipping 275 matching lines @@
      */
     historyData: function()
     {
         // FIXME: do we need to copy this?
         return this._data;
     },
 
     /**
      * @override
      * @param {string} prefix
-     * @return {!Array.<string>}
+     * @return {!Array.<{title: string, className: (string|undefined)}>}

[dgozman, 2016/03/24 18:39:34]

WebInspector.SuggestBox.Suggestions

      */
     additionalCompletions: function(prefix)
     {
         if (!this.isCaretAtEndOfPrompt())
             return [];
         var result = [];
         var text = this.text();
+        var set = new Set();
         for (var i = this._data.length - 1; i >= 0 && result.length < 50; --i) {
             var item = this._data[i];
             if (!item.startsWith(text))
                 continue;
-            result.push(item.substring(text.length - prefix.length));
+            if (set.has(item))
+                continue;
+            set.add(item);
+            result.push({title: item.substring(text.length - prefix.length), className: "additional"});
         }
         return result;
     },
 
     /**
      * @param {!Array.<string>} data
      */
     setHistoryData: function(data)
     {
         this._data = [].concat(data);
@@ skipping 115 matching lines @@
 
             return;
         }
 
         WebInspector.TextPrompt.prototype.onKeyDown.apply(this, arguments);
     },
 
     __proto__: WebInspector.TextPrompt.prototype
 }