mojo api for view based lockscreen

ash/login/ui/lock_contents_view.cc

Index: ash/login/ui/lock_contents_view.cc
diff --git a/ash/login/ui/lock_contents_view.cc b/ash/login/ui/lock_contents_view.cc
index c676efb97b06675117c0f5b336b1f2d337ff4d07..bf038d4159f6b302c6d0804bda4538f224187f29 100644
--- a/ash/login/ui/lock_contents_view.cc
+++ b/ash/login/ui/lock_contents_view.cc
@@ -4,6 +4,9 @@
 
 #include "ash/login/ui/lock_contents_view.h"
 
+#include "ash/login/lock_screen_controller.h"
+#include "ash/session/session_controller.h"
+#include "ash/shell.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
@@ -33,8 +36,14 @@ void LockContentsView::ButtonPressed(views::Button* sender,
                                      const ui::Event& event) {
   DCHECK(unlock_button_ == sender);
 
-  // TODO: Run mojo call that talks to backend which unlocks the device.
-  NOTIMPLEMENTED();
+  // TODO: user index shouldn't be hard coded here. Complete the implementation
+  // below.
+  const int kUserIndex = 0;
+  SessionController* session_controller = Shell::Get()->session_controller();
+  const mojom::UserSession* const user_session =
+      session_controller->GetUserSession(kUserIndex);
+  Shell::Get()->lock_screen_controller()->AuthenticateUser(
+      user_session->account_id, std::string(), false);
 }
 
 }  // namespace ash