Add OAuth2 authentication for some voice transcription requests.

chrome/browser/ui/app_list/speech_auth_helper.cc

+// 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.
+
+#include "chrome/browser/ui/app_list/speech_auth_helper.h"
+
+#include <string>
+
+#include "base/bind.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/signin/profile_oauth2_token_service_factory.h"
+#include "chrome/browser/signin/signin_manager_factory.h"
+#include "components/signin/core/browser/profile_oauth2_token_service.h"
+#include "components/signin/core/browser/signin_manager.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace app_list {
+
+static const char* kAuthScope =
+    "https://www.googleapis.com/auth/webhistory";
+static const int kMinTokenRefreshDelaySeconds = 300;  // 5 minutes
+
+
+SpeechAuthHelper::SpeechAuthHelper(Profile* profile)
+    : OAuth2TokenService::Consumer(kAuthScope),
+      profile_(profile),
+      token_service_(ProfileOAuth2TokenServiceFactory::GetForProfile(profile)),
+      weak_factory_(this) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  // If token_service_ is NULL, we can't do anything. This might be NULL if the
+  // profile is a guest user.
+  if (!token_service_)
+    return;
+
+  SigninManagerBase* signin_manager =
+      SigninManagerFactory::GetForProfile(profile);
+  // Again, this might be NULL, and if it is, we can't proceed.
+  if (!signin_manager)
+    return;
+
+  authenticated_account_id_ = signin_manager->GetAuthenticatedAccountId();
+  if (!token_service_->RefreshTokenIsAvailable(authenticated_account_id_)) {
+    // Wait for the OAuth2 refresh token to be available before trying to obtain
+    // a speech token.
+    token_service_->AddObserver(this);
+  } else {
+    FetchAuthToken();
+  }
+}
+
+SpeechAuthHelper::~SpeechAuthHelper() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  if (token_service_)
+    token_service_->RemoveObserver(this);

[calamity, 2014/12/10 02:26:13]

If the refresh token is available, I would expect this to DCHECK that you're
removing an observer that was never added.

[Anand Mistry (off Chromium), 2014/12/10 03:52:14]

It doesn't. RemoveObserver() gracefully handles NULL and the observer not being
in the list.

+}
+
+void SpeechAuthHelper::OnGetTokenSuccess(
+    const OAuth2TokenService::Request* request,
+    const std::string& access_token,
+    const base::Time& expiration_time) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  auth_token_ = access_token;
+  auth_token_request_.reset();
+
+  base::Time now = base::Time::Now();
+  base::TimeDelta delay = expiration_time - now;
+  if (delay.InSeconds() < kMinTokenRefreshDelaySeconds)
+    delay = base::TimeDelta::FromSeconds(kMinTokenRefreshDelaySeconds);
+  ScheduleTokenFetch(delay);
+}
+
+void SpeechAuthHelper::OnGetTokenFailure(
+    const OAuth2TokenService::Request* request,
+    const GoogleServiceAuthError& error) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  auth_token_ = "";
+  auth_token_request_.reset();
+
+  // Try again later.
+  // TODO(amistry): Implement backoff.
+  ScheduleTokenFetch(
+      base::TimeDelta::FromSeconds(kMinTokenRefreshDelaySeconds));
+}
+
+void SpeechAuthHelper::OnRefreshTokenAvailable(const std::string& account_id) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  if (authenticated_account_id_ == account_id)
+    FetchAuthToken();
+}
+
+void SpeechAuthHelper::ScheduleTokenFetch(const base::TimeDelta& fetch_delay) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  content::BrowserThread::PostDelayedTask(
+      content::BrowserThread::UI,
+      FROM_HERE,
+      base::Bind(&SpeechAuthHelper::FetchAuthToken,
+                 weak_factory_.GetWeakPtr()),
+      fetch_delay);
+}
+
+void SpeechAuthHelper::FetchAuthToken() {
+  // The process of fetching and refreshing OAuth tokens is started from the
+  // consustructor, and so token_service_ and authenticated_account_id_ are
+  // guaranteed to be valid at this point.
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  OAuth2TokenService::ScopeSet scopes;
+  scopes.insert(kAuthScope);
+  auth_token_request_ = token_service_->StartRequest(
+      authenticated_account_id_,
+      scopes,
+      this);
+}
+
+std::string SpeechAuthHelper::GetToken() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  return auth_token_;
+}
+
+std::string SpeechAuthHelper::GetScope() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  return kAuthScope;
+}
+
+}  // namespace app_list