DevTools: do not show autocomplete suggestions that already exist

Completions in the middle of the text will not show SuggestBox
if one of the suggestions already exists in the editor.

Diff GIF: https://imgur.com/a/1Ry9Ser

Bug: none
Change-Id: I3bd27fa58b6a36c963e08f10f90e4747882f77e3
Reviewed-on: https://chromium-review.googlesource.com/1050503Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Joel Einbinder <einbinder@chromium.org>
Commit-Queue: Erik Luo <luoe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559306}

third_party/WebKit/LayoutTests/http/tests/devtools/console/console-correct-suggestions-expected.txt

 Tests that console correctly finds suggestions in complicated cases.
 
+Checking 'window.|foo'
+Found: _foo
+
+Checking 'window._|foo'
+Not Found: _foo
+
+Checking 'window._|foo' forcefully
+Found: _foo
+
 Checking 'window.do'
 Found: document
 
@@ -128,6 +137,14 @@ Checking 'I|mag'
 Found: Image
 Found: Infinity
 
+Checking 'I|mage'
+Not Found: Image
+Not Found: Infinity
+
+Checking 'I|mage' forcefully
+Found: Image
+Found: Infinity
+
 Checking 'var x = (do|);'
 Found: document
 

third_party/WebKit/LayoutTests/http/tests/devtools/console/console-correct-suggestions.js

@@ -19,6 +19,7 @@
     function shouldNotFindThisFunction() { }
     function shouldFindThisFunction() { }
     window["should not find this"] = true;
+    window._foo = true;
     var myMap = new Map([['first', 1], ['second', 2], ['third', 3], ['shouldNotFindThis', 4]]);
     var complicatedObject = {
         'foo-bar': true,
@@ -104,6 +105,9 @@
   sequential([
     () => ConsoleTestRunner.waitUntilConsoleEditorLoaded().then(
         e => consoleEditor = e),
+    () => testCompletions('window.|foo', ['_foo']),
+    () => testCompletions('window._|foo', ['_foo'], false),
+    () => testCompletions('window._|foo', ['_foo'], true),
     () => testCompletions('window.do', ['document']),
     () => testCompletions('win', ['window']),
     () => testCompletions('window["doc', ['"document"]']),
@@ -150,6 +154,8 @@
     () => testCompletions('document[   [win', ['window']),
     () => testCompletions('document[   [  win', ['window']),
     () => testCompletions('I|mag', ['Image', 'Infinity']),
+    () => testCompletions('I|mage', ['Image', 'Infinity'], false),
+    () => testCompletions('I|mage', ['Image', 'Infinity'], true),
     () => testCompletions('var x = (do|);', ['document']),
     () => testCompletions('complicatedObject["foo', ['"foo-bar"]']),
     () => testCompletions('complicatedObject["foo-', ['"foo-bar"]']),

third_party/blink/renderer/devtools/front_end/console/ConsolePrompt.js

@@ -356,7 +356,7 @@ Console.ConsolePrompt = class extends UI.Widget {
    * @param {boolean=} force
    * @return {!Promise<!UI.SuggestBox.Suggestions>}
    */
-  _wordsWithQuery(queryRange, substituteRange, force) {
+  async _wordsWithQuery(queryRange, substituteRange, force) {
     const query = this._editor.text(queryRange);
     const before = this._editor.text(new TextUtils.TextRange(0, 0, queryRange.startLine, queryRange.startColumn));
     const historyWords = this._historyCompletions(query, force);
@@ -369,10 +369,15 @@ Console.ConsolePrompt = class extends UI.Widget {
       if (!trimmedBefore.endsWith('.'))
         excludedTokens.add('js-property');
       if (excludedTokens.has(token.type))
-        return Promise.resolve(historyWords);
+        return historyWords;
     }
-    return ObjectUI.javaScriptAutocomplete.completionsForTextInCurrentContext(before, query, force)
-        .then(words => words.concat(historyWords));
+    const words = await ObjectUI.javaScriptAutocomplete.completionsForTextInCurrentContext(before, query, force);
+    if (!force && !this._isCaretAtEndOfPrompt()) {
+      const queryAndAfter = this._editor.line(queryRange.startLine).substring(queryRange.startColumn);
+      if (queryAndAfter && words.some(word => queryAndAfter.startsWith(word.text) && query.length !== word.text.length))
+        return [];
+    }
+    return words.concat(historyWords);
   }
 
   /**