Integrate UI with authentication flow.

blimp/client/core/blimp_client_context_internal.h

Index: blimp/client/core/blimp_client_context_internal.h
diff --git a/blimp/client/core/blimp_client_context_internal.h b/blimp/client/core/blimp_client_context_internal.h
new file mode 100644
index 0000000000000000000000000000000000000000..9b394f424f779663bd4d594ab6d4b793cded520c
--- /dev/null
+++ b/blimp/client/core/blimp_client_context_internal.h
@@ -0,0 +1,25 @@
+// Copyright 2016 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 BLIMP_CLIENT_CORE_BLIMP_CLIENT_CONTEXT_INTERNAL_H_
+#define BLIMP_CLIENT_CORE_BLIMP_CLIENT_CONTEXT_INTERNAL_H_
+
+#include "base/macros.h"
+#include "blimp/client/core/session/identity_source.h"
+
+namespace blimp {
+namespace client {
+
+// BlimpClientInternal is a Blimp internal interface used for decoupling
+// internal build components from blimp/client/core/context build target.
+// This interface can depends on any Blimp targets except context.
+class BlimpClientContextInternal {
+ public:
+  virtual IdentitySource* GetIdentitySource() = 0;

[David Trainor- moved to gerrit, 2016/08/29 05:12:24]

This looks like it's only implemented on Android, will this compile on linux? 
Could we just have an IdentitySourceProvider class in the settings package that
this can implement or build?  Or just pass the IdentitySource when we create the
dialog?

[xingliu, 2016/08/30 04:47:42]

Done, sorry this is my bad, I've done it in Java so in c++ it's already directly
pass the IdentitySource. So removed this file.  

+};
+
+}  // namespace client
+}  // namespace blimp
+
+#endif  // BLIMP_CLIENT_CORE_BLIMP_CLIENT_CONTEXT_INTERNAL_H_