Decoupling visibility states from webcontent, adding visibility management in ResourceManager

athena/activity/public/activity_view_model.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_VIEW_MODEL_H_
 #define ATHENA_ACTIVITY_PUBLIC_ACTIVITY_VIEW_MODEL_H_
 
 #include "athena/athena_export.h"
 #include "base/strings/string16.h"
 
 typedef unsigned int SkColor;
 
 namespace gfx {
 class ImageSkia;
 }
 
 namespace views {
 class View;
 }
 
 namespace athena {
 
 // The view model for the representation of the activity.
 class ATHENA_EXPORT ActivityViewModel {
  public:
   virtual ~ActivityViewModel() {}
 
-  // Called after the view model is attached to the widget/window tree.
+  // Called after the view model is attached to the widget/window tree and
+  // before it gets registered to the ActivityManager and the ResourceManager.
+  // At this time the Activity can also be moved to a different place in the
+  // Activity history.
   virtual void Init() = 0;
 
   // Returns a color most representative of this activity.
   virtual SkColor GetRepresentativeColor() const = 0;
 
   // Returns a title for the activity.
   virtual base::string16 GetTitle() const = 0;
 
   // True if the activity wants to use Widget's frame, or false if the activity
   // draws its own frame.
@@ skipping 13 matching lines @@
   // overview mode. The returned image can have no size if either a view exists
   // or the activity has not yet been loaded. In that case
   // GetRepresentativeColor() should be used to clear the preview area.
   // Note: We intentionally do not use a layer / view for this.
   virtual gfx::ImageSkia GetOverviewModeImage() = 0;
 };
 
 }  // namespace athena
 
 #endif  // ATHENA_ACTIVITY_PUBLIC_ACTIVITY_VIEW_MODEL_H_