Add a "Keepalive count" column to Task Manager.

chrome/browser/task_manager/test_task_manager.h

 // 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.
 
 #ifndef CHROME_BROWSER_TASK_MANAGER_TEST_TASK_MANAGER_H_
 #define CHROME_BROWSER_TASK_MANAGER_TEST_TASK_MANAGER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 49 matching lines @@
                             int* out_error_code) const override;
   int64_t GetNetworkUsage(TaskId task_id) const override;
   int64_t GetProcessTotalNetworkUsage(TaskId task_id) const override;
   int64_t GetSqliteMemoryUsed(TaskId task_id) const override;
   bool GetV8Memory(TaskId task_id,
                    int64_t* allocated,
                    int64_t* used) const override;
   bool GetWebCacheStats(
       TaskId task_id,
       blink::WebCache::ResourceTypeStats* stats) const override;
+  int GetKeepaliveCount(TaskId task_id) const override;
   const TaskIdList& GetTaskIdsList() const override;
   TaskIdList GetIdsOfTasksSharingSameProcess(TaskId task_id) const override;
   size_t GetNumberOfTasksOnSameProcess(TaskId task_id) const override;
   TaskId GetTaskIdForWebContents(
       content::WebContents* web_contents) const override;
 
   base::TimeDelta GetRefreshTime();
   int64_t GetEnabledFlags();
 
  protected:
   // task_manager::TaskManager:
   void Refresh() override {}
   void StartUpdating() override {}
   void StopUpdating() override {}
 
   base::ProcessHandle handle_;
   base::ProcessId pid_;
   base::string16 title_;
   std::string rappor_sample_;
   gfx::ImageSkia icon_;
   TaskIdList ids_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TestTaskManager);
 };
 
 }  // namespace task_manager
 
 #endif  // CHROME_BROWSER_TASK_MANAGER_TEST_TASK_MANAGER_H_