WIP - loop in LayoutManager for preferred size changes

ui/views/view.h

 // Copyright (c) 2012 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 UI_VIEWS_VIEW_H_
 #define UI_VIEWS_VIEW_H_
 
 #include <algorithm>
 #include <map>
 #include <set>
@@ skipping 56 matching lines @@
 class LayoutManager;
 class NativeViewAccessibility;
 class ScrollView;
 class Widget;
 
 namespace internal {
 class PostEventDispatchHandler;
 class RootView;
 }
 
+class VIEWS_EXPORT ScopedMaybeLayout {
+ public:
+  ScopedMaybeLayout(views::View* view);
+  ~ScopedMaybeLayout();
+
+ private:
+  views::View* view_;
+};
+
 /////////////////////////////////////////////////////////////////////////////
 //
 // View class
 //
 //   A View is a rectangle within the views View hierarchy. It is the base
 //   class for all Views.
 //
 //   A View is a container of other Views (there is no such thing as a Leaf
 //   View - makes code simpler, reduces type conversion headaches, design
 //   mistakes etc)
@@ skipping 881 matching lines @@
     // Whether the press may generate a drag.
     bool possible_drag;
 
     // Coordinates of the mouse press.
     gfx::Point start_pt;
   };
 
   // Size and disposition ------------------------------------------------------
 
   // Override to be notified when the bounds of the view have changed.
-  virtual void OnBoundsChanged(const gfx::Rect& previous_bounds);
+  virtual void OnBoundsChanged(const gfx::Rect& previous_bounds) {}
 
   // Called when the preferred size of a child view changed.  This gives the
   // parent an opportunity to do a fresh layout if that makes sense.
-  virtual void ChildPreferredSizeChanged(View* child) {}
+  virtual void ChildPreferredSizeChanged(View* child);
 
   // Called when the visibility of a child view changed.  This gives the parent
   // an opportunity to do a fresh layout if that makes sense.
   virtual void ChildVisibilityChanged(View* child) {}
 
   // Invalidates the layout and calls ChildPreferredSizeChanged on the parent
   // if there is one. Be sure to call View::PreferredSizeChanged when
   // overriding such that the layout is properly invalidated.
   virtual void PreferredSizeChanged();
 
@@ skipping 198 matching lines @@
   // the views hierarchy. The above function gives the class the flexibility to
   // decide which object should be used to obtain the children, but this
   // function makes the decision explicit.
   std::string DoPrintViewGraph(bool first, View* view_with_children);
 #endif
 
  private:
   friend class internal::PostEventDispatchHandler;
   friend class internal::RootView;
   friend class FocusManager;
+  friend class LayoutManager;
+  friend class ScopedMaybeLayout;
   friend class Widget;
 
   // Painting  -----------------------------------------------------------------
 
   enum SchedulePaintType {
     // Indicates the size is the same (only the origin changed).
     SCHEDULE_PAINT_SIZE_SAME,
 
     // Indicates the size changed (and possibly the origin).
     SCHEDULE_PAINT_SIZE_CHANGED
@@ skipping 327 matching lines @@
   // Belongs to this view, but it's reference-counted on some platforms
   // so we can't use a scoped_ptr. It's dereferenced in the destructor.
   NativeViewAccessibility* native_view_accessibility_;
 
   DISALLOW_COPY_AND_ASSIGN(View);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEW_H_