components/view_manager/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_VIEW_MANAGER_SERVER_VIEW_DRAWN_TRACKER_H_
   6 #define COMPONENTS_VIEW_MANAGER_SERVER_VIEW_DRAWN_TRACKER_H_
   7
   8 #include <set>
   9
  10 #include "base/basictypes.h"
  11 #include "components/view_manager/server_view_observer.h"
  12
  13 namespace view_manager {
  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* root,
  24                          ServerView* view,
  25                          ServerViewDrawnTrackerObserver* observer);
  26   ~ServerViewDrawnTracker() override;
  27
  28   ServerView* view() { return view_; }
  29
  30  private:
  31   void SetDrawn(ServerView* ancestor, bool drawn);
  32
  33   // Adds |this| as an observer to |view_| and its ancestors.
  34   void AddObservers();
  35
  36   // Stops observerving any views we added as an observer in AddObservers().
  37   void RemoveObservers();
  38
  39   // ServerViewObserver:
  40   void OnViewDestroyed(ServerView* view) override;
  41   void OnViewHierarchyChanged(ServerView* view,
  42                               ServerView* new_parent,
  43                               ServerView* old_parent) override;
  44   void OnViewVisibilityChanged(ServerView* view) override;
  45
  46   ServerView* root_;
  47   ServerView* view_;
  48   ServerViewDrawnTrackerObserver* observer_;
  49   bool drawn_;
  50   // Set of views we're observing. This is |view_| and all its ancestors.
  51   std::set<ServerView*> views_;
  52
  53   DISALLOW_COPY_AND_ASSIGN(ServerViewDrawnTracker);
  54 };
  55
  56 }  // namespace view_manager
  57
  58 #endif  // COMPONENTS_VIEW_MANAGER_SERVER_VIEW_DRAWN_TRACKER_H_