components/view_manager/server_view_delegate.h

   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 COMPONENTS_VIEW_MANAGER_SERVER_VIEW_DELEGATE_H_
   6 #define COMPONENTS_VIEW_MANAGER_SERVER_VIEW_DELEGATE_H_
   7
   8 #include "components/view_manager/public/interfaces/view_manager_constants.mojom.h"
   9
  10 namespace gfx {
  11 class Rect;
  12 }
  13
  14 namespace mojo {
  15 class ViewportMetrics;
  16 }
  17
  18 namespace view_manager {
  19
  20 class ServerView;
  21
  22 // ServerViewDelegate is notified at key points in the lifetime of a
  23 // ServerView. Some of the functions are similar to that of
  24 // ServerViewObserver. For example, ServerViewDelegate::PrepareToDestroyView()
  25 // and ServerViewObserver::OnWillDestroyView(). The key difference between
  26 // the two are the ServerViewDelegate ones are always notified first, and
  27 // ServerViewDelegate gets non-const arguments.
  28 class ServerViewDelegate {
  29  public:
  30   // Invoked when a view is about to be destroyed; before any of the children
  31   // have been removed and before the view has been removed from its parent.
  32   virtual void PrepareToDestroyView(ServerView* view) = 0;
  33
  34   virtual void PrepareToChangeViewHierarchy(ServerView* view,
  35                                             ServerView* new_parent,
  36                                             ServerView* old_parent) = 0;
  37
  38   virtual void PrepareToChangeViewVisibility(ServerView* view) = 0;
  39
  40   virtual void OnScheduleViewPaint(const ServerView* view) = 0;
  41
  42   // Returns the root of the view tree to which this |view| is attached. Returns
  43   // null if this view is not attached up through to a root view.
  44   virtual const ServerView* GetRootView(const ServerView* view) const = 0;
  45
  46  protected:
  47   virtual ~ServerViewDelegate() {}
  48 };
  49
  50 }  // namespace view_manager
  51
  52 #endif  // COMPONENTS_VIEW_MANAGER_SERVER_VIEW_DELEGATE_H_