Add a "Keepalive count" column to Task Manager.

chrome/browser/task_manager/providers/task.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_manager/providers/task.h"
 
 #include <stddef.h>
 
 #include "base/process/process.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 125 matching lines @@
 }
 
 bool Task::ReportsWebCacheStats() const {
   return false;
 }
 
 blink::WebCache::ResourceTypeStats Task::GetWebCacheStats() const {
   return blink::WebCache::ResourceTypeStats();
 }
 
+int Task::GetKeepaliveCount() const {
+  return -1;
+}
+
 bool Task::ReportsNetworkUsage() const {
   return network_usage_ != -1;
 }
 
 }  // namespace task_manager