DevTools: Remove check for windows path forward slashes

This fixes issue #958651 Workspace name includes full URL on Windows.

The removed check causes the problem because on windows the file path
has already been normalized to file path URLs like: file://C:/example
but the check was added assuming on windows file paths would look like:
C:\\example which has not been the case since https://crrev.com/cf0a07b13661965f1c3df642306850b69cfeda8c

Screenshot: https://i.imgur.com/py7oc8u.png
Bug: 958651
Change-Id: I4eca2b29df0f550f3dc952e33b4782273b2e76a1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1658680Reviewed-by: Erik Luo <luoe@chromium.org>
Commit-Queue: John Emau <johnemau@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#676648}

third_party/blink/renderer/devtools/front_end/persistence/WorkspaceSettingsTab.js

@@ -105,7 +105,7 @@ Persistence.WorkspaceSettingsTab = class extends UI.VBox {
    */
   _renderFileSystem(fileSystem) {
     const fileSystemPath = fileSystem.path();
-    const lastIndexOfSlash = fileSystemPath.lastIndexOf(Host.isWin() ? '\\' : '/');
+    const lastIndexOfSlash = fileSystemPath.lastIndexOf('/');
     const folderName = fileSystemPath.substr(lastIndexOfSlash + 1);
 
     const element = createElementWithClass('div', 'file-system-container');

third_party/blink/web_tests/http/tests/devtools/workspace-view-file-system-header-expected.txt

+Tests workspace view file system headers
+
+File system name: test
+File system path: file:///this/is/a/test
+

third_party/blink/web_tests/http/tests/devtools/workspace-view-file-system-header.js

+// Copyright 2019 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.
+
+(async function() {
+  TestRunner.addResult('Tests workspace view file system headers\n');
+  await TestRunner.loadModule('bindings_test_runner');
+
+  const fs = new BindingsTestRunner.TestFileSystem('file:///this/is/a/test');
+  await fs.reportCreatedPromise();
+
+  await UI.viewManager.showView('workspace');
+  const workspaceElement = (await UI.viewManager.view('workspace').widget()).element;
+
+  const fsName = workspaceElement.querySelector('.file-system-name').textContent;
+  const fsPath = workspaceElement.querySelector('.file-system-path').textContent;
+
+  TestRunner.addResult(`File system name: ${fsName}`);
+  TestRunner.addResult(`File system path: ${fsPath}`);
+
+  TestRunner.completeTest();
+})();