[NTP Snippets] Schedule periodic fetching

components/ntp_snippets/ntp_snippets_fetcher.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 "components/ntp_snippets/ntp_snippets_fetcher.h"
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/path_service.h"
 #include "base/strings/stringprintf.h"
 #include "base/task_runner_util.h"
@@ skipping 39 matching lines @@
 NTPSnippetsFetcher::NTPSnippetsFetcher(
     scoped_refptr<base::SequencedTaskRunner> file_task_runner,
     SigninManager* signin_manager,
     OAuth2TokenService* token_service,
     URLRequestContextGetter* url_request_context_getter)
     : OAuth2TokenService::Consumer("NTP_snippets"),
       file_task_runner_(file_task_runner),
       url_request_context_getter_(url_request_context_getter),
       signin_manager_(signin_manager),
       token_service_(token_service),
+      waiting_for_refresh_token_(false),
       weak_ptr_factory_(this) {}
 
 NTPSnippetsFetcher::~NTPSnippetsFetcher() {}
 
 scoped_ptr<NTPSnippetsFetcher::SnippetsAvailableCallbackList::Subscription>
 NTPSnippetsFetcher::AddCallback(const SnippetsAvailableCallback& callback) {
   return callback_list_.Add(callback);
 }
 
 void NTPSnippetsFetcher::FetchSnippets(bool overwrite) {
@@ skipping 12 matching lines @@
   if (exists) {
     NotifyObservers();
   } else {
     StartFetch();
   }
 }
 
 void NTPSnippetsFetcher::StartFetch() {
   if (signin_manager_->IsAuthenticated()) {
     StartTokenRequest();
-  } else {
+  } else if (!waiting_for_refresh_token_) {
     // Wait until we get a refresh token.
     token_service_->AddObserver(this);
+    waiting_for_refresh_token_ = true;
   }
 }
 
 void NTPSnippetsFetcher::StartTokenRequest() {
   OAuth2TokenService::ScopeSet scopes;
   scopes.insert(kApiScope);
   oauth_request_ = token_service_->StartRequest(
       signin_manager_->GetAuthenticatedAccountId(), scopes, this);
 }
 
@@ skipping 30 matching lines @@
     const GoogleServiceAuthError& error) {
   oauth_request_.reset();
   DLOG(ERROR) << "Unable to get token: " << error.ToString();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // OAuth2TokenService::Observer overrides
 void NTPSnippetsFetcher::OnRefreshTokenAvailable(
     const std::string& account_id) {
   token_service_->RemoveObserver(this);
+  waiting_for_refresh_token_ = false;
   StartTokenRequest();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // URLFetcherDelegate overrides
 void NTPSnippetsFetcher::OnURLFetchComplete(const URLFetcher* source) {
   DCHECK_EQ(url_fetcher_.get(), source);
 
   const URLRequestStatus& status = source->GetStatus();
   if (!status.is_success()) {
@@ skipping 23 matching lines @@
   if (!success) {
     DLOG(WARNING) << "Could not move file to "
                   << GetSnippetsSuggestionsPath().LossyDisplayName();
     return;
   }
 
   NotifyObservers();
 }
 
 }  // namespace ntp_snippets