Integrate UI with authentication flow.

blimp/client/core/blimp_client_context_impl.h

Index: blimp/client/core/blimp_client_context_impl.h
diff --git a/blimp/client/core/blimp_client_context_impl.h b/blimp/client/core/blimp_client_context_impl.h
index 8302d26ca19bdb5617f7f005a4755092e5c6a8ad..7c8d6e588929159df70e86cd3013473edda85b79 100644
--- a/blimp/client/core/blimp_client_context_impl.h
+++ b/blimp/client/core/blimp_client_context_impl.h
@@ -43,6 +43,8 @@ class BlimpClientContextImpl : public BlimpClientContext,
       scoped_refptr<base::SingleThreadTaskRunner> file_thread_task_runner);
   ~BlimpClientContextImpl() override;
 
+  IdentitySource* GetIdentitySource();
+
   // BlimpClientContext implementation.
   void SetDelegate(BlimpClientContextDelegate* delegate) override;
   std::unique_ptr<BlimpContents> CreateBlimpContents() override;
@@ -59,6 +61,13 @@ class BlimpClientContextImpl : public BlimpClientContext,
   // the AssignmentSource.
   virtual GURL GetAssignerURL();
 
+  // Create IdentitySource which provides user sign in states and OAuth2 token
+  // service.
+  void CreateIdentitySource();
+
+  // Provide OAuth2 token and propagate account sign in states change.
+  std::unique_ptr<IdentitySource> identity_source_;
+
  private:
   // Connect to assignment source with OAuth2 token to get an assignment.
   virtual void ConnectToAssignmentSource(const std::string& client_auth_token);
@@ -96,9 +105,6 @@ class BlimpClientContextImpl : public BlimpClientContext,
 
   std::unique_ptr<ThreadPipeManager> thread_pipe_manager_;
 
-  // Provide OAuth2 token and propagate account sign in states change.
-  std::unique_ptr<IdentitySource> identity_source_;
-
   base::WeakPtrFactory<BlimpClientContextImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BlimpClientContextImpl);