[PrintingPage] Fix "Saved printers" search tag when no saved printers

Fixes the behavior of the "Saved Printers" search tag so it is
dynamically added/removed when the number of saved printers is greater
than 0.

Bug: 1116553
Change-Id: I37f2d3c1612ec58feb01a4dcdf426807fd442040
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2424518
Commit-Queue: Daniel Classon <dclasson@google.com>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Jimmy Gong <jimmyxgong@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809985}

chrome/browser/ui/webui/settings/chromeos/printing_section.cc

@@ -13,6 +13,7 @@
 #include "chrome/common/url_constants.h"
 #include "chrome/grit/generated_resources.h"
 #include "chromeos/constants/chromeos_features.h"
+#include "chromeos/printing/printer_configuration.h"
 #include "content/public/browser/web_ui_data_source.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/webui/web_ui_util.h"
@@ -29,12 +30,6 @@ const std::vector<SearchConcept>& GetPrintingSearchConcepts() {
        mojom::SearchResultDefaultRank::kMedium,
        mojom::SearchResultType::kSetting,
        {.setting = mojom::Setting::kAddPrinter}},
-      {IDS_OS_SETTINGS_TAG_PRINTING_SAVED_PRINTERS,
-       mojom::kPrintingDetailsSubpagePath,
-       mojom::SearchResultIcon::kPrinter,
-       mojom::SearchResultDefaultRank::kMedium,
-       mojom::SearchResultType::kSetting,
-       {.setting = mojom::Setting::kSavedPrinters}},
       {IDS_OS_SETTINGS_TAG_PRINTING,
        mojom::kPrintingDetailsSubpagePath,
        mojom::SearchResultIcon::kPrinter,
@@ -47,6 +42,18 @@ const std::vector<SearchConcept>& GetPrintingSearchConcepts() {
   return *tags;
 }
 
+const std::vector<SearchConcept>& GetSavedPrintersSearchConcepts() {
+  static const base::NoDestructor<std::vector<SearchConcept>> tags({
+      {IDS_OS_SETTINGS_TAG_PRINTING_SAVED_PRINTERS,
+       mojom::kPrintingDetailsSubpagePath,
+       mojom::SearchResultIcon::kPrinter,
+       mojom::SearchResultDefaultRank::kMedium,
+       mojom::SearchResultType::kSetting,
+       {.setting = mojom::Setting::kSavedPrinters}},
+  });
+  return *tags;
+}
+
 const std::vector<SearchConcept>& GetPrintingManagementSearchConcepts() {
   static const base::NoDestructor<std::vector<SearchConcept>> tags({
       {IDS_OS_SETTINGS_TAG_PRINT_MANAGEMENT,
@@ -77,9 +84,19 @@ PrintingSection::PrintingSection(Profile* profile,
   updater.AddSearchTags(GetPrintingSearchConcepts());
   if (IsPrintManagementEnabled())
     updater.AddSearchTags(GetPrintingManagementSearchConcepts());
+
+  // Saved Printers search tags are added/removed dynamically.
+  if (printers_manager_) {
+    printers_manager_->AddObserver(this);
+    UpdateSavedPrintersSearchTags();
+  }
 }
 
-PrintingSection::~PrintingSection() = default;
+PrintingSection::~PrintingSection() {
+  if (printers_manager_) {
+    printers_manager_->RemoveObserver(this);
+  }
+}
 
 void PrintingSection::AddLoadTimeData(content::WebUIDataSource* html_source) {
   static constexpr webui::LocalizedString kLocalizedStrings[] = {
@@ -274,5 +291,22 @@ void PrintingSection::RegisterHierarchy(HierarchyGenerator* generator) const {
                             kPrintingDetailsSettings, generator);
 }
 
+void PrintingSection::OnPrintersChanged(PrinterClass printer_class,
+                                        const std::vector<Printer>& printers) {
+  UpdateSavedPrintersSearchTags();
+}
+
+void PrintingSection::UpdateSavedPrintersSearchTags() {
+  // Start with no saved printers search tags.
+  SearchTagRegistry::ScopedTagUpdater updater = registry()->StartUpdate();
+  updater.RemoveSearchTags(GetSavedPrintersSearchConcepts());
+
+  std::vector<Printer> saved_printers =
+      printers_manager_->GetPrinters(PrinterClass::kSaved);
+  if (!saved_printers.empty()) {
+    updater.AddSearchTags(GetSavedPrintersSearchConcepts());
+  }
+}
+
 }  // namespace settings
 }  // namespace chromeos

chrome/browser/ui/webui/settings/chromeos/printing_section.h

@@ -5,6 +5,7 @@
 #ifndef CHROME_BROWSER_UI_WEBUI_SETTINGS_CHROMEOS_PRINTING_SECTION_H_
 #define CHROME_BROWSER_UI_WEBUI_SETTINGS_CHROMEOS_PRINTING_SECTION_H_
 
+#include "chrome/browser/chromeos/printing/cups_printers_manager.h"
 #include "chrome/browser/ui/webui/settings/chromeos/os_settings_section.h"
 
 namespace content {
@@ -20,7 +21,8 @@ namespace settings {
 class SearchTagRegistry;
 
 // Provides UI strings and search tags for Printing settings.
-class PrintingSection : public OsSettingsSection {
+class PrintingSection : public OsSettingsSection,
+                        public CupsPrintersManager::Observer {
  public:
   PrintingSection(Profile* profile,
                   SearchTagRegistry* search_tag_registry,
@@ -37,6 +39,12 @@ class PrintingSection : public OsSettingsSection {
   std::string GetSectionPath() const override;
   void RegisterHierarchy(HierarchyGenerator* generator) const override;
 
+  // CupsPrintersManager::Observer
+  void OnPrintersChanged(PrinterClass printer_class,
+                         const std::vector<Printer>& printers) override;
+
+  void UpdateSavedPrintersSearchTags();
+
   CupsPrintersManager* printers_manager_;
 };