Create a visible shelf and constrain window movement

ui/aura_shell/toplevel_layout_manager.cc

Index: ui/aura_shell/toplevel_layout_manager.cc
diff --git a/ui/aura_shell/toplevel_layout_manager.cc b/ui/aura_shell/toplevel_layout_manager.cc
index 05d5f474c23de0cebb1c12be25236c296ed5cd6d..0826c1d1361a316c176a92d79af208f268416d6b 100644
--- a/ui/aura_shell/toplevel_layout_manager.cc
+++ b/ui/aura_shell/toplevel_layout_manager.cc
@@ -48,7 +48,14 @@ void ToplevelLayoutManager::OnChildWindowVisibilityChanged(aura::Window* child,
 
 void ToplevelLayoutManager::SetChildBounds(aura::Window* child,
                                            const gfx::Rect& requested_bounds) {
-  SetChildBoundsDirect(child, requested_bounds);
+  const static int kTitleHeight = 12;
+  gfx::Rect child_bounds(requested_bounds);
+  const gfx::Rect shelf_bounds = shelf_->GetLauncherBounds();

[sky, 2011/12/14 06:23:05]

I think it would be better to ask for the screen work area rather than go to the
shelf directly. That way if we allow the shelf to move to a side, or have other
things effect the work area this code won't change.

[DaveMoore, 2011/12/14 17:03:19]

Done.

+  if (child_bounds.y() < 0)
+    child_bounds.set_y(0);
+  else if (child_bounds.y() + kTitleHeight > shelf_bounds.y())
+    child_bounds.set_y(shelf_bounds.y() - kTitleHeight);
+  SetChildBoundsDirect(child, child_bounds);
 }
 
 void ToplevelLayoutManager::OnWindowPropertyChanged(aura::Window* window,