Record PendingTaskCount when a backgrounded renderer is suspended.

third_party/WebKit/Source/platform/scheduler/child/idle_helper.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 THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_CHILD_IDLE_HELPER_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_CHILD_IDLE_HELPER_H_
 
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "platform/scheduler/base/cancelable_closure_holder.h"
@@ skipping 125 matching lines @@
   base::TimeTicks WillProcessIdleTask() override;
   void DidProcessIdleTask() override;
 
   // base::MessageLoop::TaskObserver implementation:
   void WillProcessTask(const base::PendingTask& pending_task) override;
   void DidProcessTask(const base::PendingTask& pending_task) override;
 
   IdlePeriodState SchedulerIdlePeriodState() const;
   static const char* IdlePeriodStateToString(IdlePeriodState state);
 
+  int GetNumberOfPendingIdleTasks();

[Sami, 2016/10/14 01:38:18]

size_t

[tasak, 2016/10/14 05:55:31]

I agree. 
...so I found that we don't need this method. Because I added
GetNumberOfPendingTasks to TaskQueueManager (and also SchedulerHelper).

+
  private:
   friend class BaseIdleHelperTest;
   friend class IdleHelperTest;
 
   class State {
    public:
     State(SchedulerHelper* helper,
           Delegate* delegate,
           const char* tracing_category,
           const char* disabled_by_default_tracing_category,
@@ skipping 76 matching lines @@
   base::WeakPtr<IdleHelper> weak_idle_helper_ptr_;
   base::WeakPtrFactory<IdleHelper> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(IdleHelper);
 };
 
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_CHILD_IDLE_HELPER_H_