NTP Snippets: Added error codes for out of quota events

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 <stdlib.h>
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ skipping 68 matching lines @@
     case NTPSnippetsFetcher::FetchResult::URL_REQUEST_STATUS_ERROR:
       return "URLRequestStatus error";
     case NTPSnippetsFetcher::FetchResult::HTTP_ERROR:
       return "HTTP error";
     case NTPSnippetsFetcher::FetchResult::JSON_PARSE_ERROR:
       return "Received invalid JSON";
     case NTPSnippetsFetcher::FetchResult::INVALID_SNIPPET_CONTENT_ERROR:
       return "Invalid / empty list.";
     case NTPSnippetsFetcher::FetchResult::OAUTH_TOKEN_ERROR:
       return "Error in obtaining an OAuth2 access token.";
+    case NTPSnippetsFetcher::FetchResult::INTERACTIVE_QUOTA_ERROR:
+      return "Out of interactive quota.";
+    case NTPSnippetsFetcher::FetchResult::NON_INTERACTIVE_QUOTA_ERROR:
+      return "Out of non-interactive quota.";
     case NTPSnippetsFetcher::FetchResult::RESULT_MAX:
       break;
   }
   NOTREACHED();
   return "Unknown error";
 }
 
+bool isFetchPreconditionFailed(NTPSnippetsFetcher::FetchResult result) {

[Marc Treib, 2016/08/25 14:19:05]

nit: IsFetchPreconditionFailed (start with a capital letter)

+  switch (result) {
+    case NTPSnippetsFetcher::FetchResult::EMPTY_HOSTS:
+    case NTPSnippetsFetcher::FetchResult::OAUTH_TOKEN_ERROR:
+    case NTPSnippetsFetcher::FetchResult::INTERACTIVE_QUOTA_ERROR:
+    case NTPSnippetsFetcher::FetchResult::NON_INTERACTIVE_QUOTA_ERROR:
+      return true;
+    default:

[Marc Treib, 2016/08/25 14:19:05]

Instead of a default, I'd prefer to list the values explicitly. Then, when
someone adds a new value but doesn't list it here, they'll get a compile error.

+      return false;
+  }
+}
+
 std::string GetFetchEndpoint() {
   std::string endpoint = variations::GetVariationParamValue(
       ntp_snippets::kStudyName, kContentSuggestionsBackend);
   return endpoint.empty() ? kChromeReaderServer : endpoint;
 }
 
 bool UsesChromeContentSuggestionsAPI(const GURL& endpoint) {
   if (endpoint == GURL(kChromeReaderServer)) {
     return false;
   } else if (endpoint != GURL(kContentSuggestionsServer) &&
@@ skipping 105 matching lines @@
 void NTPSnippetsFetcher::SetCallback(
     const SnippetsAvailableCallback& callback) {
   snippets_available_callback_ = callback;
 }
 
 void NTPSnippetsFetcher::FetchSnippetsFromHosts(
     const std::set<std::string>& hosts,
     const std::string& language_code,
     int count,
     bool interactive_request) {
-  if (!request_throttler_.DemandQuotaForRequest(interactive_request))
+  if (!request_throttler_.DemandQuotaForRequest(interactive_request)) {
+    FetchFinished(
+        OptionalSnippets(),
+        interactive_request ?
+          FetchResult::INTERACTIVE_QUOTA_ERROR :

[Marc Treib, 2016/08/25 14:19:05]

nit: wrong indentation I think? (You could try "git cl format")

+          FetchResult::NON_INTERACTIVE_QUOTA_ERROR,
+          /*extra_message=*/std::string());
     return;
+  }
 
   hosts_ = hosts;
   fetch_start_time_ = tick_clock_->NowTicks();
 
   if (UsesHostRestrictions() && hosts_.empty()) {
     FetchFinished(OptionalSnippets(), FetchResult::EMPTY_HOSTS,
                   /*extra_message=*/std::string());
     return;
   }
 
@@ skipping 345 matching lines @@
       OptionalSnippets(), FetchResult::JSON_PARSE_ERROR,
       /*extra_message=*/base::StringPrintf(" (error %s)", error.c_str()));
 }
 
 void NTPSnippetsFetcher::FetchFinished(OptionalSnippets snippets,
                                        FetchResult result,
                                        const std::string& extra_message) {
   DCHECK(result == FetchResult::SUCCESS || !snippets);
   last_status_ = FetchResultToString(result) + extra_message;
 
-  // If the result is EMPTY_HOSTS or OAUTH_TOKEN_ERROR, we didn't actually send
-  // a network request, so don't record FetchTime in those cases.
-  if (result != FetchResult::EMPTY_HOSTS &&
-      result != FetchResult::OAUTH_TOKEN_ERROR) {
+  // Don't record FetchTimes if the result indicates that a precondition
+  // failed and we never actually sent a network request
+  if (!isFetchPreconditionFailed(result)) {
     UMA_HISTOGRAM_TIMES("NewTabPage.Snippets.FetchTime",
                         tick_clock_->NowTicks() - fetch_start_time_);
   }
   UMA_HISTOGRAM_ENUMERATION("NewTabPage.Snippets.FetchResult",
                             static_cast<int>(result),
                             static_cast<int>(FetchResult::RESULT_MAX));
 
   if (!snippets_available_callback_.is_null())
     snippets_available_callback_.Run(std::move(snippets));
 }
 
 }  // namespace ntp_snippets