Convert //chrome from scoped_ptr to std::unique_ptr

chrome/app_shim/chrome_main_app_mode_mac.mm

Index: chrome/app_shim/chrome_main_app_mode_mac.mm
diff --git a/chrome/app_shim/chrome_main_app_mode_mac.mm b/chrome/app_shim/chrome_main_app_mode_mac.mm
index 72e751bede9bcd03b775c4b0ff8b6290d9b355b2..af4b62a0db5f066c584fc0b7c2b5d4186eb10ce8 100644
--- a/chrome/app_shim/chrome_main_app_mode_mac.mm
+++ b/chrome/app_shim/chrome_main_app_mode_mac.mm
@@ -141,7 +141,7 @@ class AppShimController : public IPC::Listener {
   void Close();
 
   base::FilePath user_data_dir_;
-  scoped_ptr<IPC::ChannelProxy> channel_;
+  std::unique_ptr<IPC::ChannelProxy> channel_;
   base::scoped_nsobject<AppShimDelegate> delegate_;
   bool launch_app_done_;
   bool ping_chrome_reply_received_;