Remove RuntimeAPIDelegate::GetPreviousVersion.

extensions/shell/browser/shell_runtime_api_delegate.cc

 // Copyright 2014 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 "extensions/shell/browser/shell_runtime_api_delegate.h"
 
 #include "build/build_config.h"
 #include "extensions/common/api/runtime.h"
 
 #if defined(OS_CHROMEOS)
@@ skipping 10 matching lines @@
 
 ShellRuntimeAPIDelegate::~ShellRuntimeAPIDelegate() {
 }
 
 void ShellRuntimeAPIDelegate::AddUpdateObserver(UpdateObserver* observer) {
 }
 
 void ShellRuntimeAPIDelegate::RemoveUpdateObserver(UpdateObserver* observer) {
 }
 
-base::Version ShellRuntimeAPIDelegate::GetPreviousExtensionVersion(
-    const Extension* extension) {
-  return base::Version();
-}
-
 void ShellRuntimeAPIDelegate::ReloadExtension(const std::string& extension_id) {
 }
 
 bool ShellRuntimeAPIDelegate::CheckForUpdates(
     const std::string& extension_id,
     const UpdateCheckCallback& callback) {
   return false;
 }
 
 void ShellRuntimeAPIDelegate::OpenURL(const GURL& uninstall_url) {
@@ skipping 12 matching lines @@
 // We allow chrome.runtime.restart() to request a device restart on ChromeOS.
 #if defined(OS_CHROMEOS)
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->RequestRestart();
   return true;
 #endif
   *error_message = "Restart is only supported on ChromeOS.";
   return false;
 }
 
 }  // namespace extensions