mash: Convert FocusCycler to wm common types and move to //ash/common

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 cffcd3ade478c1a7d2fe80d91eeac2b263fa9471..626eabe0be78c3b5ef60dfb6c7b5a872fa53a441 100644
--- a/ash/common/wm_shell.cc
+++ b/ash/common/wm_shell.cc
@@ -4,6 +4,7 @@
 
 #include "ash/common/wm_shell.h"
 
+#include "ash/common/focus_cycler.h"
 #include "ash/common/system/tray/system_tray_delegate.h"
 #include "ash/common/system/tray/wm_system_tray_notifier.h"
 #include "base/logging.h"
@@ -23,7 +24,9 @@ WmShell* WmShell::Get() {
   return instance_;
 }
 
-WmShell::WmShell() : system_tray_notifier_(new WmSystemTrayNotifier) {}
+WmShell::WmShell()
+    : focus_cycler_(new FocusCycler),
+      system_tray_notifier_(new WmSystemTrayNotifier) {}
 
 WmShell::~WmShell() {}