Make activities have a thick border when in overview mode part 1

athena/activity/public/activity_view_model.h

Index: athena/activity/public/activity_view_model.h
diff --git a/athena/activity/public/activity_view_model.h b/athena/activity/public/activity_view_model.h
index 9d38ecad048dfcd54fa48ccc706b7613c8e742a1..a1ebceeaf26dc638a8833247ed71a4a5652ea44d 100644
--- a/athena/activity/public/activity_view_model.h
+++ b/athena/activity/public/activity_view_model.h
@@ -54,6 +54,12 @@ class ATHENA_EXPORT ActivityViewModel {
   // 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;
+
+  // Prepares the contents view for overview.
+  virtual void PrepareContentsForOverview() = 0;
+
+  // Undoes any changes done by PrepareContentsForOverview().
+  virtual void ResetContentsView() = 0;
 };
 
 }  // namespace athena