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      1 // Copyright 2014 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef ATHENA_RESOURCE_MANAGER_PUBLIC_RESOURCE_MANAGER_H_
      6 #define ATHENA_RESOURCE_MANAGER_PUBLIC_RESOURCE_MANAGER_H_
      7 
      8 #include "athena/athena_export.h"
      9 #include "athena/resource_manager/memory_pressure_notifier.h"
     10 #include "base/basictypes.h"
     11 
     12 namespace athena {
     13 
     14 // The resource manager is monitoring activity changes, low memory conditions
     15 // and other events to control the activity state (pre-/un-/re-/loading them)
     16 // to keep enough memory free that no jank/lag will show when new applications
     17 // are loaded and / or a navigation between applications takes place.
     18 class ATHENA_EXPORT ResourceManager {
     19  public:
     20   // Creates the instance handling the resources.
     21   static void Create();
     22   static ResourceManager* Get();
     23   static void Shutdown();
     24 
     25   ResourceManager();
     26   virtual ~ResourceManager();
     27 
     28   // Unit tests can simulate MemoryPressure changes with this call.
     29   // Note: Even though the default unit test ResourceManagerDelegte
     30   // implementation ensures that the MemoryPressure event will not go off,
     31   // this call will also explicitly stop the MemoryPressureNotifier.
     32   virtual void SetMemoryPressureAndStopMonitoring(
     33       MemoryPressureObserver::MemoryPressure pressure) = 0;
     34 
     35   // Resource management calls require time to show effect (until memory
     36   // gets actually released). This function lets override the time limiter
     37   // between two calls to allow for more/less aggressive timeouts.
     38   // By calling this function, the next call to the Resource manager will be
     39   // executed immediately.
     40   virtual void SetWaitTimeBetweenResourceManageCalls(int time_in_ms) = 0;
     41 
     42   // Suspend the resource manager temporarily if |pause| is set. This can be
     43   // called before e.g. re-arranging the order of activities. Once called with
     44   // |pause| == false any queued operations will be performed and the resource
     45   // manager will continue its work.
     46   virtual void Pause(bool pause) = 0;
     47 
     48  private:
     49   DISALLOW_COPY_AND_ASSIGN(ResourceManager);
     50 };
     51 
     52 // Use this scoped object to pause/restart the resource manager.
     53 class ScopedPauseResourceManager {
     54  public:
     55   ScopedPauseResourceManager() {
     56     ResourceManager::Get()->Pause(true);
     57   }
     58   ~ScopedPauseResourceManager() {
     59     ResourceManager::Get()->Pause(false);
     60   }
     61  private:
     62   DISALLOW_COPY_AND_ASSIGN(ScopedPauseResourceManager);
     63 };
     64 
     65 }  // namespace athena
     66 
     67 #endif  // ATHENA_RESOURCE_MANAGER_PUBLIC_RESOURCE_MANAGER_H_
     68