Aura: Add --aura-laptop-mode to fill the workspace with a single window.

ui/aura_shell/shell.h

Index: ui/aura_shell/shell.h
diff --git a/ui/aura_shell/shell.h b/ui/aura_shell/shell.h
index a8778636de91c6e209dbfe497d64b0cfb669360c..936cb2630414f59d28dd30737042b36bfd3fa689 100644
--- a/ui/aura_shell/shell.h
+++ b/ui/aura_shell/shell.h
@@ -18,6 +18,7 @@
 
 namespace aura {
 class EventFilter;
+class RootWindow;
 class Window;
 }
 namespace gfx {
@@ -77,6 +78,8 @@ class AURA_SHELL_EXPORT Shell {
   }
 
   ShellDelegate* delegate() { return delegate_.get(); }
+
+  // May return NULL if we're not using a launcher (e.g. laptop-mode).
   Launcher* launcher() { return launcher_.get(); }
 
   // Made available for tests.
@@ -91,6 +94,7 @@ class AURA_SHELL_EXPORT Shell {
   virtual ~Shell();
 
   void Init();
+  void InitLayoutManagers(aura::RootWindow* root_window);
 
   // Enables WorkspaceManager.
   void EnableWorkspaceManager();