Clean up Assignment Create in BlimpClientContextImpl.

blimp/client/core/session/identity_source.h

Index: blimp/client/core/session/identity_source.h
diff --git a/blimp/client/core/session/identity_source.h b/blimp/client/core/session/identity_source.h
index 30663102f5a05dc9fd066e93921a531ee97c4055..d86a0a450c1613a59ccf0e1d299154dd9b4242b6 100644
--- a/blimp/client/core/session/identity_source.h
+++ b/blimp/client/core/session/identity_source.h
@@ -23,9 +23,12 @@ class IdentitySource : public OAuth2TokenService::Consumer,
                        public OAuth2TokenService::Observer,
                        public IdentityProvider::Observer {
  public:
-  typedef base::Callback<void(const std::string&)> TokenCallback;
+  using TokenCallback = base::Callback<void(const std::string&)>;
+  using TokenErrorCallback =
+      base::Callback<void(const GoogleServiceAuthError&)>;
 
-  explicit IdentitySource(BlimpClientContextDelegate* delegate,
+  explicit IdentitySource(std::unique_ptr<IdentityProvider> identity_provider,
+                          const TokenErrorCallback& error_callback,
                           const TokenCallback& callback);
   ~IdentitySource() override;
 
@@ -63,6 +66,8 @@ class IdentitySource : public OAuth2TokenService::Consumer,
   // OAuth2TokenService::Consumer callback get called.
   std::unique_ptr<OAuth2TokenService::Request> token_request_;
 
+  TokenErrorCallback error_callback_;
+
   // Callback after OAuth2 token is fetched.
   TokenCallback token_callback_;
 
@@ -76,8 +81,6 @@ class IdentitySource : public OAuth2TokenService::Consumer,
   // Current retry count due to request cancellation.
   int retry_times_;
 
-  BlimpClientContextDelegate* delegate_;
-
   DISALLOW_COPY_AND_ASSIGN(IdentitySource);
 };