[NTP] Undoing the first custom link action will uninitialize custom links

Undoing the first custom link action (i.e. the action that initializes
custom links) will now uninitialize custom links.
Screencast: https://screencast.googleplex.com/cast/NTM5NDQzOTE1MzM4NTQ3Mnw3MDNkZTY0Yy1hZQ

Bug: 881256
Change-Id: I8d77fef71b581d5b6b81ce369d21afd8eb717c31
Reviewed-on: https://chromium-review.googlesource.com/c/1272137
Commit-Queue: Kristi Park <kristipark@chromium.org>
Reviewed-by: Mathieu Perreault <mathp@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599394}

chrome/browser/search/instant_service.cc

@@ -309,11 +309,8 @@ void InstantService::UndoAllMostVisitedDeletions() {
 }
 
 bool InstantService::AddCustomLink(const GURL& url, const std::string& title) {
-  if (most_visited_sites_) {
-    // Initializes custom links if they have not been initialized yet.
-    most_visited_sites_->InitializeCustomLinks();
+  if (most_visited_sites_)
     return most_visited_sites_->AddCustomLink(url, base::UTF8ToUTF16(title));
-  }
   return false;
 }
 
@@ -321,8 +318,6 @@ bool InstantService::UpdateCustomLink(const GURL& url,
                                       const GURL& new_url,
                                       const std::string& new_title) {
   if (most_visited_sites_) {
-    // Initializes custom links if they have not been initialized yet.
-    most_visited_sites_->InitializeCustomLinks();
     return most_visited_sites_->UpdateCustomLink(url, new_url,
                                                  base::UTF8ToUTF16(new_title));
   }
@@ -330,11 +325,8 @@ bool InstantService::UpdateCustomLink(const GURL& url,
 }
 
 bool InstantService::DeleteCustomLink(const GURL& url) {
-  if (most_visited_sites_) {
-    // Initializes custom links if they have not been initialized yet.
-    most_visited_sites_->InitializeCustomLinks();
+  if (most_visited_sites_)
     return most_visited_sites_->DeleteCustomLink(url);
-  }
   return false;
 }
 

components/ntp_tiles/most_visited_sites.cc

@@ -252,14 +252,17 @@ void MostVisitedSites::InitializeCustomLinks() {
   if (!custom_links_ || !current_tiles_.has_value() || !custom_links_enabled_)
     return;
 
-  if (custom_links_->Initialize(current_tiles_.value()))
+  if (custom_links_->Initialize(current_tiles_.value())) {
+    custom_links_action_count_ = 0;
     BuildCurrentTiles();
+  }
 }
 
 void MostVisitedSites::UninitializeCustomLinks() {
   if (!custom_links_ || !custom_links_enabled_)
     return;
 
+  custom_links_action_count_ = -1;
   custom_links_->Uninitialize();
   BuildCurrentTiles();
   Refresh();
@@ -284,9 +287,15 @@ bool MostVisitedSites::AddCustomLink(const GURL& url,
   if (!custom_links_ || !custom_links_enabled_)
     return false;
 
+  // Initialize custom links if they have not been initialized yet.
+  InitializeCustomLinks();
+
   bool success = custom_links_->AddLink(url, title);
-  if (success)
+  if (success) {
+    if (custom_links_action_count_ != -1)
+      custom_links_action_count_++;
     BuildCurrentTiles();
+  }
   return success;
 }
 
@@ -296,9 +305,15 @@ bool MostVisitedSites::UpdateCustomLink(const GURL& url,
   if (!custom_links_ || !custom_links_enabled_)
     return false;
 
+  // Initialize custom links if they have not been initialized yet.
+  InitializeCustomLinks();
+
   bool success = custom_links_->UpdateLink(url, new_url, new_title);
-  if (success)
+  if (success) {
+    if (custom_links_action_count_ != -1)
+      custom_links_action_count_++;
     BuildCurrentTiles();
+  }
   return success;
 }
 
@@ -306,9 +321,15 @@ bool MostVisitedSites::DeleteCustomLink(const GURL& url) {
   if (!custom_links_ || !custom_links_enabled_)
     return false;
 
+  // Initialize custom links if they have not been initialized yet.
+  InitializeCustomLinks();
+
   bool success = custom_links_->DeleteLink(url);
-  if (success)
+  if (success) {
+    if (custom_links_action_count_ != -1)
+      custom_links_action_count_++;
     BuildCurrentTiles();
+  }
   return success;
 }
 
@@ -316,7 +337,11 @@ void MostVisitedSites::UndoCustomLinkAction() {
   if (!custom_links_ || !custom_links_enabled_)
     return;
 
-  if (custom_links_->UndoAction())
+  // If this is undoing the first action after initialization, uninitialize
+  // custom links.
+  if (custom_links_action_count_-- == 1)
+    UninitializeCustomLinks();
+  else if (custom_links_->UndoAction())
     BuildCurrentTiles();
 }
 

components/ntp_tiles/most_visited_sites.h

@@ -174,21 +174,25 @@ class MostVisitedSites : public history::TopSitesObserver,
   // when a third-party NTP is being used.
   void EnableCustomLinks(bool enable);
   // Adds a custom link. If the number of current links is maxed, returns false
-  // and does nothing. Custom links must be enabled.
+  // and does nothing. Will initialize custom links if they have not been
+  // initialized yet. Custom links must be enabled.
   bool AddCustomLink(const GURL& url, const base::string16& title);
   // Updates the URL and/or title of the custom link specified by |url|. If
   // |url| does not exist or |new_url| already exists in the custom link list,
-  // returns false and does nothing. Custom links must be enabled.
+  // returns false and does nothing. Will initialize custom links if they have
+  // not been initialized yet. Custom links must be enabled.
   bool UpdateCustomLink(const GURL& url,
                         const GURL& new_url,
                         const base::string16& new_title);
   // Deletes the custom link with the specified |url|. If |url| does not exist
-  // in the custom link list, returns false and does nothing. Custom links must
-  // be enabled.
+  // in the custom link list, returns false and does nothing. Will initialize
+  // custom links if they have not been initialized yet. Custom links must be
+  // enabled.
   bool DeleteCustomLink(const GURL& url);
   // Restores the previous state of custom links before the last action that
-  // modified them. If there was no action, does nothing. Custom links must be
-  // enabled.
+  // modified them. If there was no action, does nothing. If this is undoing the
+  // first action after initialization, uninitializes the links. Custom links
+  // must be enabled.
   void UndoCustomLinkAction();
 
   void AddOrRemoveBlacklistedUrl(const GURL& url, bool add_url);
@@ -327,6 +331,9 @@ class MostVisitedSites : public history::TopSitesObserver,
   // False if custom links is disabled and Most Visited sites should be returned
   // instead.
   bool custom_links_enabled_ = true;
+  // Number of actions after custom link initialization. Set to -1 and not
+  // incremented if custom links was not initialized during this session.
+  int custom_links_action_count_ = -1;
 
   std::unique_ptr<
       suggestions::SuggestionsService::ResponseCallbackList::Subscription>