arc: Pass auth token from Chrome to ARC instance.

components/arc/auth/arc_auth_fetcher.h

Index: components/arc/auth/arc_auth_fetcher.h
diff --git a/components/arc/auth/arc_auth_fetcher.h b/components/arc/auth/arc_auth_fetcher.h
new file mode 100644
index 0000000000000000000000000000000000000000..bf99a50db3fc9d0ccdde01c817553ac9064aac80
--- /dev/null
+++ b/components/arc/auth/arc_auth_fetcher.h
@@ -0,0 +1,63 @@
+// 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 COMPONENTS_ARC_AUTH_ARC_AUTH_FETCHER_H_
+#define COMPONENTS_ARC_AUTH_ARC_AUTH_FETCHER_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "google_apis/gaia/gaia_auth_consumer.h"
+#include "google_apis/gaia/gaia_auth_fetcher.h"
+
+class GURL;
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+namespace arc {
+
+// Fetches ARC auth code. Fetching process starts automatically on creation.
+class ArcAuthFetcher : public GaiaAuthConsumer {
+ public:
+  // Returns a result of ARC auth code fetching.
+  class Delegate {
+   public:
+    // Called when code was fetched.
+    virtual void OnAuthCodeFetched(const std::string& code) = 0;
+    // Called when additional UI authorization is required.
+    virtual void OnAuthCodeNeedUI() = 0;
+    // Called when auth code cannot be received.
+    virtual void OnAuthCodeFailed() = 0;
+
+   protected:
+    virtual ~Delegate() = default;
+  };
+
+  ArcAuthFetcher(net::URLRequestContextGetter* getter, Delegate* delegate);
+  ~ArcAuthFetcher() override = default;
+
+  // GaiaAuthConsumer:
+  void OnClientOAuthCode(const std::string& auth_code) override;
+  void OnClientOAuthFailure(const GoogleServiceAuthError& error) override;
+
+  // Helper function to compose target URL for current user, also is used in
+  // test.
+  static GURL CreateURL();
+
+ private:
+  void FetchAuthCode();
+
+  // Unowned pointer.
+  Delegate* const delegate_;
+
+  GaiaAuthFetcher auth_fetcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(ArcAuthFetcher);
+};
+
+}  // namespace arc
+
+#endif  // COMPONENTS_ARC_AUTH_ARC_AUTH_FETCHER_H_