cros: Add pref for Launcher continue reading

This cl adds a pref to turn off Launcher continue reading feature.

Bug: 843839, 872481
Test: manual.
Change-Id: I46553972af783ebc32cdb7fbab76ae207b9474ba
Reviewed-on: https://chromium-review.googlesource.com/1168733Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581913}

chrome/browser/chromeos/preferences.cc

@@ -303,6 +303,7 @@ void Preferences::RegisterProfilePrefs(
       prefs::kUse24HourClock,
       base::GetHourClockType() == base::k24HourClock,
       user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);
+  registry->RegisterBooleanPref(prefs::kAppListContinueReadingEnabled, true);
   registry->RegisterBooleanPref(prefs::kCameraMediaConsolidated, false);
   registry->RegisterBooleanPref(
       drive::prefs::kDisableDrive, false,

chrome/browser/ui/app_list/search/app_search_provider.cc

@@ -46,6 +46,7 @@
 #include "chrome/browser/ui/app_list/search/crostini_app_result.h"
 #include "chrome/browser/ui/app_list/search/extension_app_result.h"
 #include "chrome/browser/ui/app_list/search/internal_app_result.h"
+#include "chrome/common/pref_names.h"
 #include "components/browser_sync/profile_sync_service.h"
 #include "components/sync/driver/sync_service.h"
 #include "components/sync/driver/sync_service_observer.h"
@@ -372,7 +373,9 @@ class InternalDataSource : public AppSearchProvider::DataSource,
     const base::Time time;
     for (const auto& internal_app : GetInternalAppList()) {
       if (!std::strcmp(internal_app.app_id, kInternalAppIdContinueReading) &&
-          !features::IsContinueReadingEnabled()) {
+          (!features::IsContinueReadingEnabled() ||
+           !profile()->GetPrefs()->GetBoolean(
+               prefs::kAppListContinueReadingEnabled))) {
         continue;
       }
 

chrome/common/pref_names.cc

@@ -1925,6 +1925,10 @@ const char kRemoveUsersRemoteCommand[] = "remove_users_remote_command";
 // Whether camera-produced media files have been consolidated to one place.
 const char kCameraMediaConsolidated[] = "camera_media_consolidated";
 
+// Boolean that indicates whether users can continue reading a web page when
+// they switch from phones or tablets to Chromebook.
+const char kAppListContinueReadingEnabled[] =
+    "app_list.continue_reading_enabled";
 #endif  // defined(OS_CHROMEOS)
 
 // Whether there is a Flash version installed that supports clearing LSO data.

chrome/common/pref_names.h

@@ -744,6 +744,7 @@ extern const char kMediaGalleriesRememberedGalleries[];
 extern const char kShelfChromeIconIndex[];
 extern const char kPinnedLauncherApps[];
 extern const char kPolicyPinnedLauncherApps[];
+extern const char kAppListContinueReadingEnabled[];
 #endif  // defined(OS_CHROMEOS)
 
 #if defined(OS_WIN)