[Extensions] Remove ExtensionPrefs::[Set|Get]AppDraggedByUser()

These methods (originally added in crrev.com/ef8f0ca9) were used
to mark which apps had been re-ordered on the NTP. The preference is
no longer checked anywhere.

Remove both the setter and getter, and add the preference to the list
of obsolete preferences to remove.

Bug: None
Change-Id: Ife36753fb52b5ede503fab02c839a3bf13fed824
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1836020Reviewed-by: Kelvin Jiang <kelvinjiang@chromium.org>
Reviewed-by: Evan Stade <estade@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#702488}

chrome/browser/extensions/extension_prefs_unittest.cc

@@ -641,32 +641,6 @@ class ExtensionPrefsOnExtensionInstalled : public ExtensionPrefsTest {
 TEST_F(ExtensionPrefsOnExtensionInstalled,
        ExtensionPrefsOnExtensionInstalled) {}
 
-class ExtensionPrefsAppDraggedByUser : public ExtensionPrefsTest {
- public:
-  void Initialize() override {
-    extension_ = prefs_.AddExtension("on_extension_installed");
-    EXPECT_FALSE(prefs()->WasAppDraggedByUser(extension_->id()));
-    prefs()->OnExtensionInstalled(extension_.get(),
-                                  Extension::ENABLED,
-                                  syncer::StringOrdinal(),
-                                  std::string());
-  }
-
-  void Verify() override {
-    // Set the flag and see if it persisted.
-    prefs()->SetAppDraggedByUser(extension_->id());
-    EXPECT_TRUE(prefs()->WasAppDraggedByUser(extension_->id()));
-
-    // Make sure it doesn't change on consecutive calls.
-    prefs()->SetAppDraggedByUser(extension_->id());
-    EXPECT_TRUE(prefs()->WasAppDraggedByUser(extension_->id()));
-  }
-
- private:
-  scoped_refptr<Extension> extension_;
-};
-TEST_F(ExtensionPrefsAppDraggedByUser, ExtensionPrefsAppDraggedByUser) {}
-
 class ExtensionPrefsFlags : public ExtensionPrefsTest {
  public:
   void Initialize() override {

chrome/browser/ui/webui/ntp/app_launcher_handler.cc

@@ -719,9 +719,6 @@ void AppLauncherHandler::HandleReorderApps(const base::ListValue* args) {
 
   // Don't update the page; it already knows the apps have been reordered.
   base::AutoReset<bool> auto_reset(&ignore_changes_, true);
-  ExtensionPrefs* extension_prefs =
-      ExtensionPrefs::Get(extension_service_->GetBrowserContext());
-  extension_prefs->SetAppDraggedByUser(dragged_app_id);
   ExtensionSystem::Get(extension_service_->GetBrowserContext())
       ->app_sorting()
       ->OnExtensionMoved(dragged_app_id, predecessor_to_moved_ext,

extensions/browser/extension_prefs.cc

@@ -127,9 +127,6 @@ constexpr const char kPrefAllowFileAccess[] = "newAllowFileAccess";
 // the old flag and possibly go back to that name.
 // constexpr const char kPrefAllowFileAccessOld[] = "allowFileAccess";
 
-// A preference specifying if the user dragged the app on the NTP.
-constexpr const char kPrefUserDraggedApp[] = "user_dragged_app_ntp";
-
 // Preferences that hold which permissions the user has granted the extension.
 // We explicitly keep track of these so that extensions can contain unknown
 // permissions, for backwards compatibility reasons, and we can still prompt
@@ -1529,16 +1526,6 @@ ExtensionPrefs::GetAllDelayedInstallInfo() const {
   return extensions_info;
 }
 
-bool ExtensionPrefs::WasAppDraggedByUser(
-    const std::string& extension_id) const {
-  return ReadPrefAsBooleanAndReturn(extension_id, kPrefUserDraggedApp);
-}
-
-void ExtensionPrefs::SetAppDraggedByUser(const std::string& extension_id) {
-  UpdateExtensionPref(extension_id, kPrefUserDraggedApp,
-                      std::make_unique<base::Value>(true));
-}
-
 bool ExtensionPrefs::IsFromWebStore(
     const std::string& extension_id) const {
   const base::DictionaryValue* dictionary = GetExtensionPref(extension_id);
@@ -2157,6 +2144,9 @@ void ExtensionPrefs::MigrateObsoleteExtensionPrefs() {
 
       // Added 2019-07.
       "browser_action_visible",
+
+      // Added 2019-10.
+      "user_dragged_app_ntp",
   };
 
   for (const auto& key_value : extensions_dictionary->DictItems()) {

extensions/browser/extension_prefs.h

@@ -496,14 +496,6 @@ class ExtensionPrefs : public KeyedService {
   // information.
   std::unique_ptr<ExtensionsInfo> GetAllDelayedInstallInfo() const;
 
-  // Returns true if the user repositioned the app on the app launcher via drag
-  // and drop.
-  bool WasAppDraggedByUser(const std::string& extension_id) const;
-
-  // Sets a flag indicating that the user repositioned the app on the app
-  // launcher by drag and dropping it.
-  void SetAppDraggedByUser(const std::string& extension_id);
-
   // Returns true if there is an extension which controls the preference value
   //  for |pref_key| *and* it is specific to incognito mode.
   bool HasIncognitoPrefValue(const std::string& pref_key) const;