Blimp OAuth2 token retreival on application start up.

blimp/client/core/session/identity_source.cc

+// 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.
+
+#include "blimp/client/core/session/identity_source.h"
+
+namespace blimp {
+namespace client {
+
+namespace {
+// OAuth2 token scope.
+const char kOAuth2TokenScope[] =
+    "https://www.googleapis.com/auth/userinfo.email";
+}  // namespace
+
+IdentitySource::IdentitySource(
+    std::unique_ptr<IdentityProvider> identity_provider)
+    : OAuth2TokenService::Consumer("blimp_client"),
+      identity_provider_(std::move(identity_provider)) {
+  DCHECK(identity_provider_);
+
+  identity_provider_->AddObserver(this);
+}
+
+IdentitySource::~IdentitySource() {
+  identity_provider_->RemoveActiveAccountRefreshTokenObserver(this);
+  identity_provider_->RemoveObserver(this);
+}
+
+void IdentitySource::Connect(const TokenCallback& token_callback) {
+  const std::string& account_id = identity_provider_->GetActiveAccountId();
+
+  // User must sign in first.
+  if (account_id.empty()) {
+    delegate_->OnAuthenticationError(
+        BlimpClientContextDelegate::AuthError::NOT_SIGNED_IN);
+    return;
+  }
+
+  account_id_ = account_id;
+  token_callback_ = token_callback;
+  FetchAuthToken();
+}
+
+void IdentitySource::SetDelegate(BlimpClientContextDelegate* delegate) {
+  delegate_ = delegate;
+}
+
+void IdentitySource::OnGetTokenSuccess(
+    const OAuth2TokenService::Request* request,
+    const std::string& access_token,
+    const base::Time& expiration_time) {
+  token_request_.reset();
+
+  if (token_callback_) {
+    token_callback_.Run(access_token);

[nyquist, 2016/08/16 18:38:05]

Should this reset the callback?

[xingliu, 2016/08/17 00:32:24]

Removed token callback as parameter here, instead it sets the callback right
after the ctor of identity source.

Also changed the ctor of IdentitySource, to hide some construction details. Now
IdentitySource is coupled with BlimpClientContextDelegate.

+  }
+}
+
+// Fail to get the token after retries attempts in native layer and Java layer.
+void IdentitySource::OnGetTokenFailure(

[nyquist, 2016/08/16 18:38:05]

Should this also reset the callback?

[xingliu, 2016/08/17 00:32:24]

Same as above.

+    const OAuth2TokenService::Request* request,
+    const GoogleServiceAuthError& error) {
+  token_request_.reset();
+  DCHECK(delegate_);
+  delegate_->OnAuthenticationError(
+      BlimpClientContextDelegate::AuthError::OAUTH_TOKEN_FAIL);
+}
+
+void IdentitySource::OnRefreshTokenAvailable(const std::string& account_id) {
+  if (account_id != account_id_) {
+    return;
+  }
+
+  identity_provider_->RemoveActiveAccountRefreshTokenObserver(this);
+  FetchAuthToken();
+}
+
+void IdentitySource::FetchAuthToken() {
+  OAuth2TokenService* token_service = identity_provider_->GetTokenService();
+  DCHECK(token_service);
+
+  if (token_service->RefreshTokenIsAvailable(account_id_)) {
+    OAuth2TokenService::ScopeSet scopes;
+    scopes.insert(kOAuth2TokenScope);
+    token_request_ = token_service->StartRequest(account_id_, scopes, this);
+  } else {
+    identity_provider_->AddActiveAccountRefreshTokenObserver(this);
+  }
+}
+
+}  // namespace client
+}  // namespace blimp