Add OAuth2 authentication for some voice transcription requests.

chrome/browser/ui/app_list/speech_auth_helper.h

+// 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 CHROME_BROWSER_UI_APP_LIST_SPEECH_AUTH_HELPER_H_
+#define CHROME_BROWSER_UI_APP_LIST_SPEECH_AUTH_HELPER_H_
+
+#include <string>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "components/signin/core/browser/profile_oauth2_token_service.h"
+
+class Profile;
+
+namespace app_list {
+
+// SpeechAuthHelper is a helper class to generate oauth tokens for audio
+// history. This encalsulates generating and refreshing the auth token for a
+// given profile. All functions should be called on the UI thread.
+class SpeechAuthHelper : public OAuth2TokenService::Consumer,
+                         public OAuth2TokenService::Observer {
+ public:
+  explicit SpeechAuthHelper(Profile* profile);
+  ~SpeechAuthHelper();
+
+  // Overridden from OAuth2TokenService::Consumer:
+  void OnGetTokenSuccess(const OAuth2TokenService::Request* request,
+                         const std::string& access_token,
+                         const base::Time& expiration_time) override;
+  void OnGetTokenFailure(const OAuth2TokenService::Request* request,
+                         const GoogleServiceAuthError& error) override;
+
+  // Overridden from OAuth2TokenService::Observer:
+  void OnRefreshTokenAvailable(const std::string& account_id) override;
+
+  // Returns the current auth token. If the auth service is not available, or
+  // there was a failure in obtaining a token, return the empty string.
+  std::string GetToken();
+
+  // Returns the OAuth scope associated with the auth token.
+  std::string GetScope();
+
+ private:
+  void ScheduleTokenFetch(const base::TimeDelta& fetch_delay);
+  void FetchAuthToken();
+
+  Profile* profile_;
+  std::string auth_token_;
+  scoped_ptr<OAuth2TokenService::Request> auth_token_request_;
+
+  base::WeakPtrFactory<SpeechAuthHelper> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(SpeechAuthHelper);
+};
+
+}  // namespace app_list
+
+#endif  // CHROME_BROWSER_UI_APP_LIST_SPEECH_AUTH_HELPER_H_