[Mac] Report statistics more regularly in Mac memory pressure monitor

chromecast/browser/cast_memory_pressure_monitor.h

 // Copyright 2016 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 CHROMECAST_BROWSER_CAST_MEMORY_PRESSURE_MONITOR_H_
 #define CHROMECAST_BROWSER_CAST_MEMORY_PRESSURE_MONITOR_H_
 
 #include "base/macros.h"
 #include "base/memory/memory_pressure_monitor.h"
 #include "base/memory/weak_ptr.h"
 
 namespace chromecast {
 
 // Memory pressure monitor for Cast: polls for current memory
 // usage periodically and sends memory pressure notifications.
 // TODO(halliwell): switch to //components/memory_pressure when that's
 // ready.
 class CastMemoryPressureMonitor : public base::MemoryPressureMonitor {
  public:
   CastMemoryPressureMonitor();
   ~CastMemoryPressureMonitor() override;
 
   // base::MemoryPressureMonitor implementation:
-  MemoryPressureLevel GetCurrentPressureLevel() const override;
+  MemoryPressureLevel GetCurrentPressureLevel() override;
   void SetDispatchCallback(const DispatchCallback& callback) override;
 
  private:
   void PollPressureLevel();
   void UpdateMemoryPressureLevel(MemoryPressureLevel new_level);
 
   MemoryPressureLevel current_level_;
   const int system_reserved_kb_;
   DispatchCallback dispatch_callback_;
   base::WeakPtrFactory<CastMemoryPressureMonitor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CastMemoryPressureMonitor);
 };
 
 }  // namespace chromecast
 
 #endif  // CHROMECAST_BROWSER_CAST_MEMORY_PRESSURE_MONITOR_H_