Add support for uninstalling components and use it in SupervisedUserWhitelistInstaller.

components/update_client/test/test_installer.h

 // 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.
 
 #ifndef COMPONENTS_UPDATE_CLIENT_TEST_TEST_INSTALLER_H_
 #define COMPONENTS_UPDATE_CLIENT_TEST_TEST_INSTALLER_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 13 matching lines @@
   TestInstaller();
 
   void OnUpdateError(int error) override;
 
   bool Install(const base::DictionaryValue& manifest,
                const base::FilePath& unpack_path) override;
 
   bool GetInstalledFile(const std::string& file,
                         base::FilePath* installed_file) override;
 
+  bool Uninstall() override;
+
   int error() const {
     return error_;
   }
 
   int install_count() const {
     return install_count_;
   }
 
  protected:
   ~TestInstaller() override;
@@ skipping 32 matching lines @@
  private:
   ~VersionedTestInstaller() override;
 
   base::FilePath install_directory_;
   Version current_version_;
 };
 
 }  // namespace update_client
 
 #endif  // COMPONENTS_UPDATE_CLIENT_TEST_TEST_INSTALLER_H_