Removes a data-dependent DCHECK().

components/ntp_snippets/remote/ntp_snippets_service.cc

 // Copyright 2015 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/remote/ntp_snippets_service.h"
 
 #include <algorithm>
 #include <iterator>
 #include <utility>
 
@@ skipping 551 matching lines @@
 
   // We removed some suggestions, so we want to let the client know about that.
   // The fetch might take a long time or not complete so we don't want to wait
   // for its callback.
   NotifyNewSuggestions();
 
   FetchSnippetsFromHosts(hosts, /*interactive_request=*/false);
 }
 
 void NTPSnippetsService::OnFetchFinished(
-    NTPSnippetsFetcher::OptionalSnippets snippets) {
+    NTPSnippetsFetcher::OptionalFetchedCategories fetched_categories) {
   if (!ready())
     return;
 
   for (auto& item : categories_) {
     CategoryContent* content = &item.second;
     content->provided_by_server = false;
   }
 
   // Clear up expired dismissed snippets before we use them to filter new ones.
   ClearExpiredDismissedSnippets();
 
   // If snippets were fetched successfully, update our |categories_| from each
   // category provided by the server.
-  if (snippets) {
+  if (fetched_categories) {
     // TODO(jkrcal): A bit hard to understand with so many variables called
     // "*categor*". Isn't here some room for simplification?
-    for (NTPSnippetsFetcher::FetchedCategory& fetched_category : *snippets) {
+    for (NTPSnippetsFetcher::FetchedCategory& fetched_category :
+         *fetched_categories) {
       Category category = fetched_category.category;
 
       // TODO(sfiera): Avoid hard-coding articles category checks in so many
       // places.
       if (category != articles_category_) {
         // Only update titles from server-side provided categories.
         categories_[category].localized_title =
             fetched_category.localized_title;
       }
       categories_[category].provided_by_server = true;
 
-      DCHECK_LE(snippets->size(), static_cast<size_t>(kMaxSnippetCount));
-      // TODO(sfiera): histograms for server categories.
-      // Sparse histogram used because the number of snippets is small (bound by
-      // kMaxSnippetCount).
-      if (category == articles_category_) {
+      // TODO(tschumann): Remove this histogram once we only talk to the content
+      // suggestions cloud backend.
+      if (category == articles_category_ &&
+          fetched_category.snippets.size() <= kMaxSnippetCount) {

[Marc Treib, 2016/10/06 15:36:13]

I'd prefer capping at kMaxSnippetCount, rather than not recording the histogram
at all.

[tschumann, 2016/10/06 17:57:42]

Done.

         UMA_HISTOGRAM_SPARSE_SLOWLY("NewTabPage.Snippets.NumArticlesFetched",
                                     fetched_category.snippets.size());
       }
       ReplaceSnippets(category, std::move(fetched_category.snippets));
     }
   }
 
   for (const auto& item : categories_) {
     Category category = item.first;
     UpdateCategoryStatus(category, CategoryStatus::AVAILABLE);
   }
 
   // TODO(sfiera): equivalent metrics for non-articles.
   const CategoryContent& content = categories_[articles_category_];
   UMA_HISTOGRAM_SPARSE_SLOWLY("NewTabPage.Snippets.NumArticles",
                               content.snippets.size());
   if (content.snippets.empty() && !content.dismissed.empty()) {
     UMA_HISTOGRAM_COUNTS("NewTabPage.Snippets.NumArticlesZeroDueToDiscarded",
                          content.dismissed.size());
   }
 
   // TODO(sfiera): notify only when a category changed above.
   NotifyNewSuggestions();
 
   // Reschedule after a successful fetch. This resets all currently scheduled
   // fetches, to make sure the fallback interval triggers only if no wifi fetch
   // succeeded, and also that we don't do a background fetch immediately after
   // a user-initiated one.
-  if (snippets)
+  if (fetched_categories)
     RescheduleFetching(true);
 }
 
 void NTPSnippetsService::ArchiveSnippets(Category category,
                                          NTPSnippet::PtrVector* to_archive) {
   CategoryContent* content = &categories_[category];
 
   // TODO(sfiera): handle DB for non-articles too.
   if (category == articles_category_) {
     database_->DeleteSnippets(GetSnippetIDVector(*to_archive));
@@ skipping 458 matching lines @@
 }
 
 NTPSnippetsService::CategoryContent::CategoryContent() = default;
 NTPSnippetsService::CategoryContent::CategoryContent(CategoryContent&&) =
     default;
 NTPSnippetsService::CategoryContent::~CategoryContent() = default;
 NTPSnippetsService::CategoryContent& NTPSnippetsService::CategoryContent::
 operator=(CategoryContent&&) = default;
 
 }  // namespace ntp_snippets