Make memory pressure notifier configurable

base/memory/memory_pressure_monitor_win.h

Index: base/memory/memory_pressure_monitor_win.h
diff --git a/base/memory/memory_pressure_monitor_win.h b/base/memory/memory_pressure_monitor_win.h
index 5689ac6ac74a2befa9f2fac5d749948562953437..b52a2d27bfa456a625040e640de41c48ec6f66a5 100644
--- a/base/memory/memory_pressure_monitor_win.h
+++ b/base/memory/memory_pressure_monitor_win.h
@@ -63,6 +63,7 @@ class BASE_EXPORT MemoryPressureMonitor : public base::MemoryPressureMonitor {
 
   // Get the current memory pressure level. This can be called from any thread.
   MemoryPressureLevel GetCurrentPressureLevel() const override;
+  void SetDispatchCallback(const DispatchCallback& callback) override;
 
   // Returns the moderate pressure level free memory threshold, in MB.
   int moderate_threshold_mb() const { return moderate_threshold_mb_; }
@@ -132,6 +133,8 @@ class BASE_EXPORT MemoryPressureMonitor : public base::MemoryPressureMonitor {
   // Ensures that this object is used from a single thread.
   base::ThreadChecker thread_checker_;
 
+  DispatchCallback dispatch_callback_;
+
   // Weak pointer factory to ourself used for scheduling calls to
   // CheckMemoryPressure/CheckMemoryPressureAndRecordStatistics via |timer_|.
   base::WeakPtrFactory<MemoryPressureMonitor> weak_ptr_factory_;