ScreenContext is moved to components/login.

components/login/login_export.h

Index: components/login/login_export.h
diff --git a/components/login/login_export.h b/components/login/login_export.h
new file mode 100644
index 0000000000000000000000000000000000000000..2ae7befeacd84dcde68de1b409ab92f7ddb23f0d
--- /dev/null
+++ b/components/login/login_export.h
@@ -0,0 +1,34 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_LOGIN_LOGIN_EXPORT_H_
+#define COMPONENTS_LOGIN_LOGIN_EXPORT_H_
+
+#if defined(COMPONENT_BUILD)
+
+#if defined(WIN32)
+
+#if defined(LOGIN_IMPLEMENTATION)
+#define LOGIN_EXPORT __declspec(dllexport)
+#else
+#define LOGIN_EXPORT __declspec(dllimport)
+#endif  // defined(LOGIN_IMPLEMENTATION)
+
+#else  // defined(WIN32)
+
+#if defined(LOGIN_IMPLEMENTATION)
+#define LOGIN_EXPORT __attribute__((visibility("default")))
+#else
+#define LOGIN_EXPORT
+#endif  // defined(LOGIN_IMPLEMENTATION)
+
+#endif  // defined(WIN32)
+
+#else  // defined(COMPONENT_BUILD)
+
+#define LOGIN_EXPORT
+
+#endif
+
+#endif  // COMPONENTS_LOGIN_LOGIN_EXPORT_H_