Decoupling visibility states from webcontent, adding visibility management in ResourceManager

athena/activity/public/activity.h

 // Copyright 2014 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 ATHENA_ACTIVITY_PUBLIC_ACTIVITY_H_
 #define ATHENA_ACTIVITY_PUBLIC_ACTIVITY_H_
 
 #include <string>
 
 #include "athena/athena_export.h"
@@ skipping 20 matching lines @@
 // deciding if an activity can put into a lower state then |ACTIVITY_INVISIBLE|.
 class ATHENA_EXPORT Activity {
  public:
   // The state of an activity which could either be set or requested by e.g. the
   // resource management system.
   enum ActivityState {
     // The activity is allowed to have gpu compositor layers and can be visible.
     ACTIVITY_VISIBLE,
     // The activity does not have gpu compositing layers, will not be visible
     // and will be treated as a background priority task.
+    // By transitioning from VISIBLE to INVISIBLE, a screen shot of the current
+    // web content will be taken and replaces the "active content".
     ACTIVITY_INVISIBLE,
     // The activity should surrender additional resources. This has only an
     // effect when the activity is in a loaded state (Visible, Active, Hidden).
     ACTIVITY_BACKGROUND_LOW_PRIORITY,
     // The activity will only keep a minimum set of resources to get back to the
     // running state. It will get stalled however. Note that it is not possible
     // to get into this state from the |ACTIVITY_UNLOADED| state.
     ACTIVITY_PERSISTENT,
     // Unloads the activity and can be called in any state - but unloaded.
     ACTIVITY_UNLOADED
   };
 
   // This enum declares the media state the activity is in.
   // TODO(skuhne): Move the |TabMediaState| out of chrome and combine it in a
   // media library within content and then use that enum instead.
   enum ActivityMediaState {
     ACTIVITY_MEDIA_STATE_NONE,
     ACTIVITY_MEDIA_STATE_RECORDING,  // Audio/Video being recorded by activity.
     ACTIVITY_MEDIA_STATE_CAPTURING,  // Activity is being captured.
     ACTIVITY_MEDIA_STATE_AUDIO_PLAYING  // Audible audio is playing in activity.
   };
 
-  virtual ~Activity();
+  // Delete an activity.
+  static void Delete(Activity* activity);
 
   // The Activity retains ownership of the returned view-model.
   virtual ActivityViewModel* GetActivityViewModel() = 0;
 
   // Transition the activity into a new state.
   virtual void SetCurrentState(ActivityState state) = 0;
 
   // Returns the current state of the activity.
   virtual ActivityState GetCurrentState() = 0;
 
   // Returns if the activity is visible or not.
   virtual bool IsVisible() = 0;
 
   // Returns the current media state.
   virtual ActivityMediaState GetMediaState() = 0;
 
   // Returns the window for the activity. This can be used to determine the
   // stacking order of this activity against others.
   virtual aura::Window* GetWindow() = 0;
+
+ protected:
+  virtual ~Activity() {}
 };
 
 }  // namespace athena
 
 #endif  // ATHENA_ACTIVITY_PUBLIC_ACTIVITY_H_