Make the toggle touchscreen/touchpad shortcuts apply per-user

chrome/browser/prefs/browser_prefs.cc

Index: chrome/browser/prefs/browser_prefs.cc
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 797e3e62b365f45819382df0a9027318f7b16ce6..34c1a3b6806620f9ccc5efb7cfcda98a051e53f9 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -432,7 +432,6 @@ void RegisterLocalState(PrefRegistrySimple* registry) {
   chromeos::SigninScreenHandler::RegisterPrefs(registry);
   chromeos::StartupUtils::RegisterPrefs(registry);
   chromeos::system::AutomaticRebootManager::RegisterPrefs(registry);
-  chromeos::system::InputDeviceSettings::RegisterPrefs(registry);
   chromeos::TimeZoneResolver::RegisterPrefs(registry);
   chromeos::UserImageManager::RegisterPrefs(registry);
   chromeos::UserSessionManager::RegisterPrefs(registry);
@@ -607,6 +606,7 @@ void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry) {
   chromeos::RegisterQuickUnlockProfilePrefs(registry);
   chromeos::SAMLOfflineSigninLimiter::RegisterProfilePrefs(registry);
   chromeos::ServicesCustomizationDocument::RegisterProfilePrefs(registry);
+  chromeos::system::InputDeviceSettings::RegisterProfilePrefs(registry);
   chromeos::UserImageSyncObserver::RegisterProfilePrefs(registry);
   extensions::EPKPChallengeUserKey::RegisterProfilePrefs(registry);
   flags_ui::PrefServiceFlagsStorage::RegisterProfilePrefs(registry);
@@ -706,6 +706,11 @@ void RegisterLoginProfilePrefs(user_prefs::PrefRegistrySyncable* registry) {
 
 // This method should be periodically pruned of year+ old migrations.
 void MigrateObsoleteBrowserPrefs(Profile* profile, PrefService* local_state) {
+#if defined(OS_CHROMEOS)
+  // Added 11/2016
+  local_state->ClearPref(prefs::kTouchScreenEnabled);
+  local_state->ClearPref(prefs::kTouchPadEnabled);

[afakhry, 2016/11/08 22:36:16]

Apparently the prefs have to be registered in the local state registry, but I
moved the registration to the profile registry.

This is causing multiple DCHECKS.

[gab, 2016/11/09 16:30:16]

Right, look at the paradigm for say kShownAutoLaunchInfobarDeprecated below. You
need to suppress the definition of the variable in pref_names.h, move it here in
anonymous namespace. Then still register above and clear it here.

At the same time, our practice is to have people that add such cleanup to also
remove 1+ year old cleanups (i.e. kShownAutoLaunchInfobarDeprecated
specifically) so we naturally cycle cleanups, mind doing that? Thanks

[gab, 2016/11/09 16:31:55]

I'm sorry, in your case you don't want to suppress it from pref_names.h but
you'll still want to move it to the Local State section of the files:
https://cs.chromium.org/chromium/src/chrome/common/pref_names.cc?dr&q=%22****...

(I know it's a bit of a mess...)

[gab, 2016/11/09 16:33:31]

Err.. you want to move it to the PROFILE PREFS section:
https://cs.chromium.org/chromium/src/chrome/common/pref_names.cc?dr&q=%22****...

Interestingly, it already appears to be there. So I guess it was poorly placed
before and is now made correct..!

[afakhry, 2016/11/09 17:21:46]

Done. Thanks for the clarification!
kShownAutoLaunchInfobarDeprecated is removed, and the prefs are registered in
both local state and profile until migration is complete.

+#endif  // defined(OS_CHROMEOS)
 }
 
 // This method should be periodically pruned of year+ old migrations.