TaskManager: when shown or activated, select the last active tab.

chrome/browser/task_management/test_task_manager.cc

 // Copyright 2015 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 "chrome/browser/task_management/test_task_manager.h"
 
 namespace task_management {
 
 TestTaskManager::TestTaskManager()
     : handle_(base::kNullProcessHandle),
@@ skipping 143 matching lines @@
     TaskId task_id) const {
   TaskIdList result;
   result.push_back(task_id);
   return result;
 }
 
 size_t TestTaskManager::GetNumberOfTasksOnSameProcess(TaskId task_id) const {
   return 1;
 }
 
+TaskId TestTaskManager::GetTaskIdForWebContents(
+    content::WebContents* web_contents) const {
+  return -1;
+}
+
 base::TimeDelta TestTaskManager::GetRefreshTime() {
   return GetCurrentRefreshTime();
 }
 
 int64_t TestTaskManager::GetEnabledFlags() {
   return enabled_resources_flags();
 }
 
 }  // namespace task_management