Files App: Remove unnecessary code in file tasks unit tests

There is no need to mock hasSwitch since it doesn't seem to be used
anymore, at least not in the code being tested.

BUG=912236
TEST=browser_tests --gtest_filter="FileManagerJsTest.FileTasks"

Change-Id: I78cba36159bc00074e18d635dc21ef64e7622d4c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2206871Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: François Degros <fdegros@chromium.org>
Cr-Commit-Position: refs/heads/master@{#770812}

ui/file_manager/file_manager/foreground/js/file_tasks_unittest.js

@@ -71,11 +71,6 @@ function setUp() {
 
   // Mock chome APIs.
   mockChrome = {
-    commandLinePrivate: {
-      hasSwitch: function(name, callback) {
-        callback(false);
-      },
-    },
     fileManagerPrivate: {
       DriveConnectionStateType: {
         ONLINE: 'ONLINE',
@@ -508,15 +503,6 @@ function testOpenWithMostRecentlyExecuted(callback) {
 function testOpenZipWithZipArchiver(callback) {
   const zipArchiverTaskId = 'dmboannefpncccogfdikhmhpmdnddgoe|app|open';
 
-  chrome.commandLinePrivate.hasSwitch = (name, callback) => {
-    if (name == 'enable-zip-archiver-unpacker') {
-      // This flag used to exist and was used to switch between the "Zip
-      // Unpacker" and "Zip Archiver" component extensions.
-      failWithMessage('run zip archiver', 'zip archiver flags checked');
-    }
-    callback(false);
-  };
-
   window.chrome.fileManagerPrivate.getFileTasks = (entries, callback) => {
     setTimeout(
         callback.bind(