Make ResourceReporter a client of memory coordinator

chrome/browser/chromeos/resource_reporter/resource_reporter.h

Index: chrome/browser/chromeos/resource_reporter/resource_reporter.h
diff --git a/chrome/browser/chromeos/resource_reporter/resource_reporter.h b/chrome/browser/chromeos/resource_reporter/resource_reporter.h
index 405a2d799c89fe874ff55a8847b1ab9b06260d3a..f180a41faf8a6fb0a9d1b696cf5a3e8a8360252b 100644
--- a/chrome/browser/chromeos/resource_reporter/resource_reporter.h
+++ b/chrome/browser/chromeos/resource_reporter/resource_reporter.h
@@ -13,6 +13,7 @@
 
 #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"
@@ -26,7 +27,8 @@ namespace chromeos {
 // 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.
@@ -149,6 +151,9 @@ class ResourceReporter : public task_manager::TaskManagerObserver {
   // 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.
@@ -162,6 +167,9 @@ class ResourceReporter : public task_manager::TaskManagerObserver {
   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_;