assistant: remove privacy info in launcher search

Privacy notice that searches are powered by assistant is no longer
necessary as of crbug.com/1103703. Users now see a single assistant
search result with a visible assistant icon that makes it clear
that specific search result is powered by assistant.

BUG=b:174506130
TEST=Open launcher on new account, search, see no assistant
privacy disclosure

Cq-Include-Trybots: luci.chrome.try:linux-chromeos-chrome
Change-Id: I7a587218cddeb23aec0004478861ec156d29ee72
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2567093
Commit-Queue: Jeffrey Young <[email protected]>
Reviewed-by: Gabriel Charette <[email protected]>
Reviewed-by: James Cook <[email protected]>
Reviewed-by: Xiaohui Chen <[email protected]>
Reviewed-by: Rachel Wong <[email protected]>
Reviewed-by: Toni Baržić <[email protected]>
Reviewed-by: Tao Wu <[email protected]>
Cr-Commit-Position: refs/heads/master@{#834336}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index ef712056..f74f5b50e 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -504,6 +504,15 @@
 // Deprecated 11/2020
 const char kDRMSalt[] = "settings.privacy.drm_salt";
 
+#if BUILDFLAG(IS_CHROMEOS_ASH)
+// Deprecated 12/2020
+const char kAssistantPrivacyInfoShownInLauncher[] =
+    "ash.launcher.assistant_privacy_info_shown";
+
+const char kAssistantPrivacyInfoDismissedInLauncher[] =
+    "ash.launcher.assistant_privacy_info_dismissed";
+#endif  // BUILDFLAG(IS_CHROMEOS_ASH)
+
 // Register local state used only for migration (clearing or moving to a new
 // key).
 void RegisterLocalStatePrefsForMigration(PrefRegistrySimple* registry) {
@@ -591,6 +600,12 @@
 
   registry->RegisterIntegerPref(kSettingsLaunchedPasswordChecks, 0);
   registry->RegisterStringPref(kDRMSalt, "");
+
+#if BUILDFLAG(IS_CHROMEOS_ASH)
+  registry->RegisterIntegerPref(kAssistantPrivacyInfoShownInLauncher, 0);
+  registry->RegisterBooleanPref(kAssistantPrivacyInfoDismissedInLauncher,
+                                false);
+#endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 }
 
 }  // namespace
@@ -1226,6 +1241,10 @@
 #if BUILDFLAG(IS_CHROMEOS_ASH)
   // Added 11/2020.
   profile_prefs->ClearPref(kSupervisedUserAllowlists);
+
+  // Added 12/2020
+  profile_prefs->ClearPref(kAssistantPrivacyInfoShownInLauncher);
+  profile_prefs->ClearPref(kAssistantPrivacyInfoDismissedInLauncher);
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
   // Please don't delete the following line. It is used by PRESUBMIT.py.