Add views::View::set_preferred_size, use it in a few places.

ui/views/view.cc

Index: ui/views/view.cc
diff --git a/ui/views/view.cc b/ui/views/view.cc
index b39da4994275cb5067ff16a1f2cfbb886fcac57f..59f4d3bb3c0bda2155b01b391accb5d3d770c6de 100644
--- a/ui/views/view.cc
+++ b/ui/views/view.cc
@@ -422,9 +422,11 @@ gfx::Rect View::GetBoundsInScreen() const {
 }
 
 gfx::Size View::GetPreferredSize() const {
+  if (preferred_size_)
+    return *preferred_size_;
   if (layout_manager_.get())
     return layout_manager_->GetPreferredSize(this);
-  return gfx::Size();
+  return CalculatePreferredSize();
 }
 
 int View::GetBaseline() const {
@@ -1477,6 +1479,10 @@ bool View::HasObserver(const ViewObserver* observer) const {
 
 // Size and disposition --------------------------------------------------------
 
+gfx::Size View::CalculatePreferredSize() const {
+  return gfx::Size();
+}
+
 void View::OnBoundsChanged(const gfx::Rect& previous_bounds) {
 }