Refactor extension handling code from AppShimHost into ExtensionAppShimHandler.

apps/app_shim/app_shim_host_manager_mac.h

Index: apps/app_shim/app_shim_host_manager_mac.h
diff --git a/apps/app_shim/app_shim_host_manager_mac.h b/apps/app_shim/app_shim_host_manager_mac.h
index 13283ee980665f1fe488da4799985829870dfc39..45d881c56e71da50a186cabd8a61217b61e86161 100644
--- a/apps/app_shim/app_shim_host_manager_mac.h
+++ b/apps/app_shim/app_shim_host_manager_mac.h
@@ -5,9 +5,8 @@
 #ifndef CHROME_BROWSER_WEB_APPLICATIONS_APP_SHIM_HOST_MANAGER_MAC_H_
 #define CHROME_BROWSER_WEB_APPLICATIONS_APP_SHIM_HOST_MANAGER_MAC_H_
 
-#include "base/mac/scoped_cftyperef.h"
+#include "apps/app_shim/extension_app_shim_handler_mac.h"
 #include "base/memory/weak_ptr.h"
-#include "base/threading/thread.h"
 #include "ipc/ipc_channel_factory.h"
 
 // The AppShimHostManager receives connections from app shims on a UNIX
@@ -34,6 +33,8 @@ class AppShimHostManager
 
   scoped_ptr<IPC::ChannelFactory> factory_;
 
+  apps::ExtensionAppShimHandler extension_app_shim_handler_;
+
   DISALLOW_COPY_AND_ASSIGN(AppShimHostManager);
 };