Make OfflinePage ContentSuggestions dismissable

components/ntp_snippets/offline_pages/offline_page_suggestions_provider.cc

Index: components/ntp_snippets/offline_pages/offline_page_suggestions_provider.cc
diff --git a/components/ntp_snippets/offline_pages/offline_page_suggestions_provider.cc b/components/ntp_snippets/offline_pages/offline_page_suggestions_provider.cc
index ee8a25484f9aa172a3904d64b6e5d2d666c62368..9fa15c4928b1a03d40daf99d07d4552e4c882593 100644
--- a/components/ntp_snippets/offline_pages/offline_page_suggestions_provider.cc
+++ b/components/ntp_snippets/offline_pages/offline_page_suggestions_provider.cc
@@ -9,6 +9,10 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_task_runner_handle.h"
+#include "base/values.h"
+#include "components/ntp_snippets/pref_names.h"
+#include "components/prefs/pref_registry_simple.h"
+#include "components/prefs/pref_service.h"
 #include "ui/gfx/image/image.h"
 
 using offline_pages::MultipleOfflinePageItemResult;
@@ -26,13 +30,16 @@ const int kMaxSuggestionsCount = 5;
 OfflinePageSuggestionsProvider::OfflinePageSuggestionsProvider(
     ContentSuggestionsProvider::Observer* observer,
     CategoryFactory* category_factory,
-    OfflinePageModel* offline_page_model)
+    OfflinePageModel* offline_page_model,
+    PrefService* pref_service)
     : ContentSuggestionsProvider(observer, category_factory),
       category_status_(CategoryStatus::AVAILABLE_LOADING),
       offline_page_model_(offline_page_model),
       provided_category_(
-          category_factory->FromKnownCategory(KnownCategories::OFFLINE_PAGES)) {
+          category_factory->FromKnownCategory(KnownCategories::OFFLINE_PAGES)),
+      pref_service_(pref_service) {
   offline_page_model_->AddObserver(this);
+  ReadDismissedIDsFromPrefs();
   FetchOfflinePages();
 }
 
@@ -40,6 +47,12 @@ OfflinePageSuggestionsProvider::~OfflinePageSuggestionsProvider() {
   offline_page_model_->RemoveObserver(this);
 }
 
+// static
+void OfflinePageSuggestionsProvider::RegisterProfilePrefs(
+    PrefRegistrySimple* registry) {
+  registry->RegisterListPref(prefs::kDismissedOfflinePageSuggestions);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Private methods
 
@@ -62,8 +75,9 @@ CategoryInfo OfflinePageSuggestionsProvider::GetCategoryInfo(
 
 void OfflinePageSuggestionsProvider::DismissSuggestion(
     const std::string& suggestion_id) {
-  // TODO(pke): Implement some "dont show on NTP anymore" behaviour,
-  // then also implement ClearDismissedSuggestionsForDebugging.
+  std::string offline_page_id = GetWithinCategoryIDFromUniqueID(suggestion_id);
+  dismissed_ids_.insert(offline_page_id);
+  StoreDismissedIDsToPrefs();
 }
 
 void OfflinePageSuggestionsProvider::FetchSuggestionImage(
@@ -84,15 +98,26 @@ void OfflinePageSuggestionsProvider::ClearCachedSuggestionsForDebugging(
 std::vector<ContentSuggestion>
 OfflinePageSuggestionsProvider::GetDismissedSuggestionsForDebugging(
     Category category) {
+  // TODO(pke): Make GetDismissedSuggestionsForDebugging asynchronous so this
+  // can return proper values.
   DCHECK_EQ(category, provided_category_);
-  // TODO(pke): Implement when dismissed suggestions are supported.
-  return std::vector<ContentSuggestion>();
+  std::vector<ContentSuggestion> suggestions;
+  for (std::string dismissed_id : dismissed_ids_) {

[Marc Treib, 2016/08/11 10:28:12]

const std::string&

[Philipp Keck, 2016/08/11 12:53:19]

Done.

+    ContentSuggestion suggestion(
+        MakeUniqueID(provided_category_, dismissed_id),
+        GURL("http://dismissed-offline-page-" + dismissed_id));
+    suggestion.set_title(base::UTF8ToUTF16("Title not available"));
+    suggestions.push_back(std::move(suggestion));
+  }
+  return suggestions;
 }
 
 void OfflinePageSuggestionsProvider::ClearDismissedSuggestionsForDebugging(
     Category category) {
   DCHECK_EQ(category, provided_category_);
-  // TODO(pke): Implement when dismissed suggestions are supported.
+  dismissed_ids_.clear();
+  StoreDismissedIDsToPrefs();
+  FetchOfflinePages();
 }
 
 void OfflinePageSuggestionsProvider::OfflinePageModelLoaded(
@@ -124,21 +149,9 @@ void OfflinePageSuggestionsProvider::OnOfflinePagesLoaded(
 
   std::vector<ContentSuggestion> suggestions;
   for (const OfflinePageItem& item : result) {
-    // TODO(pke): Make sure the URL is actually opened as an offline URL.
-    // Currently, the browser opens the offline URL and then immediately
-    // redirects to the online URL if the device is online.
-    ContentSuggestion suggestion(
-        MakeUniqueID(provided_category_, base::IntToString(item.offline_id)),
-        item.GetOfflineURL());
-
-    // TODO(pke): Sort my most recently visited and only keep the top one of
-    // multiple entries for the same URL.
-    // TODO(pke): Get more reasonable data from the OfflinePageModel here.
-    suggestion.set_title(base::UTF8ToUTF16(item.url.spec()));
-    suggestion.set_snippet_text(base::string16());
-    suggestion.set_publish_date(item.creation_time);
-    suggestion.set_publisher_name(base::UTF8ToUTF16(item.url.host()));
-    suggestions.emplace_back(std::move(suggestion));
+    if (dismissed_ids_.count(base::IntToString(item.offline_id)))
+      continue;
+    suggestions.push_back(ConvertOfflinePage(item));
     if (suggestions.size() == kMaxSuggestionsCount)
       break;
   }
@@ -156,4 +169,43 @@ void OfflinePageSuggestionsProvider::NotifyStatusChanged(
   observer()->OnCategoryStatusChanged(this, provided_category_, new_status);
 }
 
+ContentSuggestion OfflinePageSuggestionsProvider::ConvertOfflinePage(
+    const OfflinePageItem& offline_page) const {
+  // TODO(pke): Make sure the URL is actually opened as an offline URL.

[Marc Treib, 2016/08/11 10:28:12]

Huh, this kinda seems like a launch blocker TBH. Do we have a tracking bug for
that? If not, please file one, and mention it here ("crbug.com/12345")

[Philipp Keck, 2016/08/11 12:53:19]

This is an open question in the PRD that Patrick hasn't addressed in a while.
I'll talk to him about it.

+  // Currently, the browser opens the offline URL and then immediately
+  // redirects to the online URL if the device is online.
+  ContentSuggestion suggestion(
+      MakeUniqueID(provided_category_,
+                   base::IntToString(offline_page.offline_id)),
+      offline_page.GetOfflineURL());
+
+  // TODO(pke): Sort my most recently visited and only keep the top one of

[Marc Treib, 2016/08/11 10:28:12]

s/my/by/

[Philipp Keck, 2016/08/11 12:53:19]

Done.

+  // multiple entries for the same URL.
+  // TODO(pke): Get more reasonable data from the OfflinePageModel here.
+  suggestion.set_title(base::UTF8ToUTF16(offline_page.url.spec()));
+  suggestion.set_snippet_text(base::string16());
+  suggestion.set_publish_date(offline_page.creation_time);
+  suggestion.set_publisher_name(base::UTF8ToUTF16(offline_page.url.host()));
+  return suggestion;
+}
+
+void OfflinePageSuggestionsProvider::ReadDismissedIDsFromPrefs() {
+  dismissed_ids_.clear();
+  const base::ListValue* list =
+      pref_service_->GetList(prefs::kDismissedOfflinePageSuggestions);
+  for (const auto& value : *list) {

[Marc Treib, 2016/08/11 10:28:12]

Might as well say base::Value instead of auto, not much longer :)

[Philipp Keck, 2016/08/11 12:53:19]

Done.

+    std::string dismissed_id;
+    bool success = value->GetAsString(&dismissed_id);
+    DCHECK(success) << "Failed to parse dismissed offline page ID from prefs";
+    dismissed_ids_.insert(dismissed_id);

[Marc Treib, 2016/08/11 10:28:12]

std::move(dismissed_id), to avoid a string copy?

[Philipp Keck, 2016/08/11 12:53:19]

I'd hope that he compiler does that for me? I inserted it.

[Marc Treib, 2016/08/11 13:13:23]

No, the compiler can't generally deduce that the variable won't be used
afterwards. There's a special case for return statements, but that's it.

[Philipp Keck, 2016/08/11 13:34:04]

It's the case for return statements because the variable goes out of scope right
after. When return-ing a member variable, for example, it doesn't do the
optimization (of course). And it's the same here: the variable goes out of scope
right after the statement.

[Marc Treib, 2016/08/11 13:41:56]

Well, try it out if you want to - I'm pretty sure the automatic-move thingie
only applies to return statements (but I'm too lazy to try it myself, or even
find the appropriate part of the standard :D).

+  }
+}
+
+void OfflinePageSuggestionsProvider::StoreDismissedIDsToPrefs() {
+  base::ListValue list;
+  for (const std::string& dismissed_id : dismissed_ids_)
+    list.AppendString(dismissed_id);
+  pref_service_->Set(prefs::kDismissedOfflinePageSuggestions, list);
+}
+
 }  // namespace ntp_snippets