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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_ACTIVITY_PUBLIC_ACTIVITY_H_
      6 #define ATHENA_ACTIVITY_PUBLIC_ACTIVITY_H_
      7 
      8 #include <string>
      9 
     10 #include "athena/athena_export.h"
     11 
     12 namespace aura {
     13 class Window;
     14 }
     15 
     16 namespace content {
     17 class WebContents;
     18 }
     19 
     20 namespace athena {
     21 
     22 class ActivityViewModel;
     23 
     24 // This class is a high level abstraction of an activity (which could be either
     25 // a web page or a V1/V2 app/extension). Through this class the activity can
     26 // be controlled (e.g. loaded / unloaded).
     27 // An Activity gets created with state |ACTIVITY_UNLOADED|.
     28 // Requesting |ACTIVITY_VISIBLE| or |ACTIVITY_INVISIBLE| will load it.
     29 // Once an activity was |ACTIVITY_INVISIBLE| for a while it can be transitioned
     30 // into |ACTIVITY_BACKGROUND_LOW_PRIORITY| to surrender more resources. After
     31 // more time it can be transitions to |ACTIVITY_PERSISTENT| in which it only
     32 // has it's runtime state left. At any time it can be transitioned back to one
     33 // of the higher levels or unloaded via |ACTIVITY_UNLOADED|.
     34 // Note that the resource manager will also query the media state before
     35 // deciding if an activity can put into a lower state then |ACTIVITY_INVISIBLE|.
     36 class ATHENA_EXPORT Activity {
     37  public:
     38   // The state of an activity which could either be set or requested by e.g. the
     39   // resource management system.
     40   enum ActivityState {
     41     // The activity is allowed to have gpu compositor layers and can be visible.
     42     ACTIVITY_VISIBLE,
     43     // The activity does not have gpu compositing layers, will not be visible
     44     // and will be treated as a background priority task.
     45     // By transitioning from VISIBLE to INVISIBLE, a screen shot of the current
     46     // web content will be taken and replaces the "active content".
     47     ACTIVITY_INVISIBLE,
     48     // The activity should surrender additional resources. This has only an
     49     // effect when the activity is in a loaded state (Visible, Active, Hidden).
     50     ACTIVITY_BACKGROUND_LOW_PRIORITY,
     51     // The activity will only keep a minimum set of resources to get back to the
     52     // running state. It will get stalled however. Note that it is not possible
     53     // to get into this state from the |ACTIVITY_UNLOADED| state.
     54     ACTIVITY_PERSISTENT,
     55     // Unloads the activity and can be called in any state - but unloaded.
     56     ACTIVITY_UNLOADED
     57   };
     58 
     59   // This enum declares the media state the activity is in.
     60   // TODO(skuhne): Move the |TabMediaState| out of chrome and combine it in a
     61   // media library within content and then use that enum instead.
     62   enum ActivityMediaState {
     63     ACTIVITY_MEDIA_STATE_NONE,
     64     ACTIVITY_MEDIA_STATE_RECORDING,  // Audio/Video being recorded by activity.
     65     ACTIVITY_MEDIA_STATE_CAPTURING,  // Activity is being captured.
     66     ACTIVITY_MEDIA_STATE_AUDIO_PLAYING  // Audible audio is playing in activity.
     67   };
     68 
     69   // Shows and activates an activity.
     70   static void Show(Activity* activity);
     71 
     72   // Deletes an activity.
     73   static void Delete(Activity* activity);
     74 
     75   // The Activity retains ownership of the returned view-model.
     76   virtual ActivityViewModel* GetActivityViewModel() = 0;
     77 
     78   // Transition the activity into a new state.
     79   virtual void SetCurrentState(ActivityState state) = 0;
     80 
     81   // Returns the current state of the activity.
     82   virtual ActivityState GetCurrentState() = 0;
     83 
     84   // Returns if the activity is visible or not.
     85   virtual bool IsVisible() = 0;
     86 
     87   // Returns the current media state.
     88   virtual ActivityMediaState GetMediaState() = 0;
     89 
     90   // Returns the window for the activity. This can be used to determine the
     91   // stacking order of this activity against others.
     92   // TODO(oshima): Consider returning base::Window window instead,
     93   // which has Show/ShowInactive and other control methods.
     94   virtual aura::Window* GetWindow() = 0;
     95 
     96   // Returns the web contents used to draw the content of the activity.
     97   // This may return NULL if the web content is not available.
     98   virtual content::WebContents* GetWebContents() = 0;
     99 
    100  protected:
    101   virtual ~Activity() {}
    102 };
    103 
    104 }  // namespace athena
    105 
    106 #endif  // ATHENA_ACTIVITY_PUBLIC_ACTIVITY_H_
    107