Moves Shell::ShowShelf() to WmShell

ash/common/wm_shell.cc

Index: ash/common/wm_shell.cc
diff --git a/ash/common/wm_shell.cc b/ash/common/wm_shell.cc
index dc9c495cb82de834c25feba6c91cf73669db83a7..7477fa7178ad625ca97c380d9f0cedf9545336fa 100644
--- a/ash/common/wm_shell.cc
+++ b/ash/common/wm_shell.cc
@@ -117,6 +117,11 @@ void WmShell::ShowContextMenu(const gfx::Point& location_in_screen,
                                                    source_type);
 }
 
+void WmShell::ShowShelf() {
+  for (WmWindow* root_window : GetAllRootWindows())
+    root_window->GetRootWindowController()->ShowShelf();
+}
+
 void WmShell::CreateShelfDelegate() {
   // May be called multiple times as shelves are created and destroyed.
   if (shelf_delegate_)