Adds a Fetch() method to the ContentSuggestionService which asks any provider to provide more conte…

components/ntp_snippets/physical_web_pages/physical_web_page_suggestions_provider.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/physical_web_pages/physical_web_page_suggestions_provider.h"
 
+#include <utility>
+
 #include "base/bind.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "grit/components_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/gfx/image/image.h"
 
 namespace ntp_snippets {
@@ skipping 67 matching lines @@
 }
 
 void PhysicalWebPageSuggestionsProvider::FetchSuggestionImage(
     const ContentSuggestion::ID& suggestion_id,
     const ImageFetchedCallback& callback) {
   // TODO(vitaliii): Implement.
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE, base::Bind(callback, gfx::Image()));
 }
 
+void PhysicalWebPageSuggestionsProvider::Fetch(
+    const Category& category,
+    const std::set<std::string>& known_suggestion_ids,
+    FetchingCallback callback) {
+  NOTREACHED();
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE,
+      base::Bind(callback, base::Passed(std::vector<ContentSuggestion>())));
+}
+
 void PhysicalWebPageSuggestionsProvider::ClearHistory(
     base::Time begin,
     base::Time end,
     const base::Callback<bool(const GURL& url)>& filter) {
   ClearDismissedSuggestionsForDebugging(provided_category_);
 }
 
 void PhysicalWebPageSuggestionsProvider::ClearCachedSuggestions(
     Category category) {
   // Ignored
@@ skipping 16 matching lines @@
 
 // Updates the |category_status_| and notifies the |observer_|, if necessary.
 void PhysicalWebPageSuggestionsProvider::NotifyStatusChanged(
     CategoryStatus new_status) {
   if (category_status_ == new_status) return;
   category_status_ = new_status;
   observer()->OnCategoryStatusChanged(this, provided_category_, new_status);
 }
 
 }  // namespace ntp_snippets