Add support for uninstalling components and use it in SupervisedUserWhitelistInstaller.

components/update_client/test/test_installer.cc

 // Copyright 2013 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.
 
 #include "components/update_client/test/test_installer.h"
 
 #include <string>
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
@@ skipping 15 matching lines @@
 }
 
 bool TestInstaller::GetInstalledFile(const std::string& file,
                                      base::FilePath* installed_file) {
   return false;
 }
 
 TestInstaller::~TestInstaller() {
 }
 
+bool TestInstaller::Uninstall() {
+  return false;
+}
+
 ReadOnlyTestInstaller::ReadOnlyTestInstaller(const base::FilePath& install_dir)
     : install_directory_(install_dir) {
 }
 
 ReadOnlyTestInstaller::~ReadOnlyTestInstaller() {
 }
 
 bool ReadOnlyTestInstaller::GetInstalledFile(const std::string& file,
                                              base::FilePath* installed_file) {
   *installed_file = install_directory_.AppendASCII(file);
@@ skipping 26 matching lines @@
 
 bool VersionedTestInstaller::GetInstalledFile(const std::string& file,
                                               base::FilePath* installed_file) {
   base::FilePath path;
   path = install_directory_.AppendASCII(current_version_.GetString());
   *installed_file = path.Append(base::FilePath::FromUTF8Unsafe(file));
   return true;
 }
 
 }  // namespace update_client