components/mus/server_view_drawn_tracker.h

   1 // Copyright 2015 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 COMPONENTS_MUS_SERVER_VIEW_DRAWN_TRACKER_H_
   6 #define COMPONENTS_MUS_SERVER_VIEW_DRAWN_TRACKER_H_
   7
   8 #include <set>
   9
  10 #include "base/basictypes.h"
  11 #include "components/mus/server_view_observer.h"
  12
  13 namespace mus {
  14
  15 class ServerViewDrawnTrackerObserver;
  16
  17 // ServerViewDrawnTracker notifies its observer any time the drawn state of
  18 // the supplied view changes.
  19 //
  20 // NOTE: you must ensure this class is destroyed before the root.
  21 class ServerViewDrawnTracker : public ServerViewObserver {
  22  public:
  23   ServerViewDrawnTracker(ServerView* view,
  24                          ServerViewDrawnTrackerObserver* observer);
  25   ~ServerViewDrawnTracker() override;
  26
  27   ServerView* view() { return view_; }
  28
  29  private:
  30   void SetDrawn(ServerView* ancestor, bool drawn);
  31
  32   // Adds |this| as an observer to |view_| and its ancestors.
  33   void AddObservers();
  34
  35   // Stops observerving any views we added as an observer in AddObservers().
  36   void RemoveObservers();
  37
  38   // ServerViewObserver:
  39   void OnViewDestroyed(ServerView* view) override;
  40   void OnViewHierarchyChanged(ServerView* view,
  41                               ServerView* new_parent,
  42                               ServerView* old_parent) override;
  43   void OnViewVisibilityChanged(ServerView* view) override;
  44
  45   ServerView* view_;
  46   ServerViewDrawnTrackerObserver* observer_;
  47   bool drawn_;
  48   // Set of views we're observing. This is |view_| and all its ancestors.
  49   std::set<ServerView*> views_;
  50
  51   DISALLOW_COPY_AND_ASSIGN(ServerViewDrawnTracker);
  52 };
  53
  54 }  // namespace mus
  55
  56 #endif  // COMPONENTS_MUS_SERVER_VIEW_DRAWN_TRACKER_H_