Make ResourceReporter a client of memory coordinator

chrome/browser/chromeos/resource_reporter/resource_reporter.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_CHROMEOS_RESOURCE_REPORTER_RESOURCE_REPORTER_H_
 #define CHROME_BROWSER_CHROMEOS_RESOURCE_REPORTER_RESOURCE_REPORTER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <string>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
+#include "base/memory/memory_coordinator_client.h"
 #include "base/memory/memory_pressure_listener.h"
 #include "base/memory/singleton.h"
 #include "chrome/browser/task_manager/task_manager_observer.h"
 #include "components/metrics/metrics_service.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/rappor/sample.h"
 
 namespace chromeos {
 
 // A system that tracks the top |kTopConsumersCount| CPU and memory consumer
 // Chrome tasks and reports a weighted random sample of them via Rappor whenever
 // memory pressure is critical. The reporting is limited to once per
 // |kMinimumTimeBetweenReportsInMS|.
-class ResourceReporter : public task_manager::TaskManagerObserver {
+class ResourceReporter : public task_manager::TaskManagerObserver,
+                         public base::MemoryCoordinatorClient {
  public:
   // A collection of the data of a task manager's task that the ResourceReporter
   // is interested in.
   struct TaskRecord {
     explicit TaskRecord(task_manager::TaskId task_id);
 
     TaskRecord(task_manager::TaskId task_id,
                const std::string& task_name,
                double cpu_percent,
                int64_t memory_bytes,
@@ skipping 102 matching lines @@
       const TaskRecord& task_record);
 
   // Gets the CPU/memory usage ranges given the |cpu| / |memory_in_bytes|
   // values.
   static CpuUsageRange GetCpuUsageRange(double cpu);
   static MemoryUsageRange GetMemoryUsageRange(int64_t memory_in_bytes);
 
   // Gets the bucket in which the current system's number of CPU cores fall.
   static CpuCoresNumberRange GetCurrentSystemCpuCoresRange();
 
+  // base::MemoryCoordinatorClient:
+  void OnMemoryStateChange(base::MemoryState state) override;
+
   // Perform a weighted random sampling to select a task by its CPU or memory
   // usage weights so that we can record samples for them via Rappor.
   // They return nullptr if no TaskRecord has been selected.
   const TaskRecord* SampleTaskByCpu() const;
   const TaskRecord* SampleTaskByMemory() const;
 
   // Does the actual recording of Rappor and UMA samples.
   void ReportSamples();
 
   // The callback function that will be invoked on memory pressure events.
   using MemoryPressureLevel = base::MemoryPressureListener::MemoryPressureLevel;
   void OnMemoryPressure(MemoryPressureLevel memory_pressure_level);
 
+  void StartRecordingCurrentState();
+  void StopRecordingCurrentState();
+
   // Monitor memory pressure events.
   std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
 
   // Contains the data about the most CPU and memory intensive tasks collected
   // at a critical memory pressure event.
   std::vector<TaskRecord> task_records_;
 
   // Either the real task manager implementation, or a test implementation in
   // unit tests.
   task_manager::TaskManagerInterface* task_manager_to_observe_;
@@ skipping 10 matching lines @@
 
   // Tracks whether monitoring started or not.
   bool is_monitoring_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourceReporter);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_RESOURCE_REPORTER_RESOURCE_REPORTER_H_