Add ShellAcceleratorController that managers global keyboard accelerators.

ui/aura_shell/shell.cc

Index: ui/aura_shell/shell.cc
diff --git a/ui/aura_shell/shell.cc b/ui/aura_shell/shell.cc
index 5f16a5bc0d1781c95bfc00620b9d80293eee5048..20af14e90738365acbe7f43e885b2b16bdd8e28f 100644
--- a/ui/aura_shell/shell.cc
+++ b/ui/aura_shell/shell.cc
@@ -17,6 +17,7 @@
 #include "ui/aura_shell/launcher/launcher.h"
 #include "ui/aura_shell/modal_container_layout_manager.h"
 #include "ui/aura_shell/shelf_layout_controller.h"
+#include "ui/aura_shell/shell_accelerator_controller.h"
 #include "ui/aura_shell/shell_delegate.h"
 #include "ui/aura_shell/shell_factory.h"
 #include "ui/aura_shell/shell_window_ids.h"
@@ -95,6 +96,7 @@ Shell* Shell::instance_ = NULL;
 
 Shell::Shell(ShellDelegate* delegate)
     : ALLOW_THIS_IN_INITIALIZER_LIST(method_factory_(this)),
+      accelerator_controller_(new ShellAcceleratorController),
       delegate_(delegate) {
   aura::Desktop::GetInstance()->SetEventFilter(
       new internal::DesktopEventFilter);