Inform server of dismissed articles.

components/ntp_snippets/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/ntp_snippets_service.h"
 
 #include <algorithm>
 #include <iterator>
 #include <utility>
 
@@ skipping 247 matching lines @@
 
 void NTPSnippetsService::FetchSnippetsFromHosts(
     const std::set<std::string>& hosts,
     bool interactive_request) {
   if (!ready())
     return;
 
   if (snippets_.empty())
     UpdateCategoryStatus(CategoryStatus::AVAILABLE_LOADING);
 
-  snippets_fetcher_->FetchSnippetsFromHosts(
-      hosts, application_language_code_, kMaxSnippetCount, interactive_request);
+  std::set<std::string> excluded_ids;
+  for (const auto& snippet : dismissed_snippets_) {
+    excluded_ids.insert(snippet->id());
+  }
+  snippets_fetcher_->FetchSnippetsFromHosts(hosts, application_language_code_,
+                                            excluded_ids, kMaxSnippetCount,
+                                            interactive_request);
 }
 
 void NTPSnippetsService::RescheduleFetching() {
   // The scheduler only exists on Android so far, it's null on other platforms.
   if (!scheduler_)
     return;
 
   if (ready()) {
     base::Time now = base::Time::Now();
     scheduler_->Schedule(
@@ skipping 607 matching lines @@
 void NTPSnippetsService::UpdateCategoryStatus(CategoryStatus status) {
   if (status == category_status_)
     return;
 
   category_status_ = status;
   observer()->OnCategoryStatusChanged(this, provided_category_,
                                       category_status_);
 }
 
 }  // namespace ntp_snippets