Add a supervised user setting to allow all cookies.

chrome/browser/supervised_user/child_accounts/child_account_service.cc

Index: chrome/browser/supervised_user/child_accounts/child_account_service.cc
diff --git a/chrome/browser/supervised_user/child_accounts/child_account_service.cc b/chrome/browser/supervised_user/child_accounts/child_account_service.cc
index c6fbe1ef1db3ee0b640d9f898197e8506e9078f0..07dda34ea1457a4852320ed9a853a166e59b3e83 100644
--- a/chrome/browser/supervised_user/child_accounts/child_account_service.cc
+++ b/chrome/browser/supervised_user/child_accounts/child_account_service.cc
@@ -152,6 +152,11 @@ bool ChildAccountService::SetActive(bool active) {
         supervised_users::kSigninAllowed,
         base::MakeUnique<base::FundamentalValue>(true));
 
+    // Always allow cookies, to avoid website compatibility issues.
+    settings_service->SetLocalSetting(
+        supervised_users::kCookiesAlwaysAllowed,
+        base::MakeUnique<base::FundamentalValue>(true));
+
     // SafeSearch is controlled at the account level, so don't override it
     // client-side.
     settings_service->SetLocalSetting(
@@ -180,8 +185,15 @@ bool ChildAccountService::SetActive(bool active) {
   } else {
     SupervisedUserSettingsService* settings_service =
         SupervisedUserSettingsServiceFactory::GetForProfile(profile_);
+    settings_service->SetLocalSetting(
+        supervised_users::kRecordHistoryIncludesSessionSync, nullptr);
     settings_service->SetLocalSetting(supervised_users::kSigninAllowed,
-                                      std::unique_ptr<base::Value>());
+                                      nullptr);
+    settings_service->SetLocalSetting(supervised_users::kCookiesAlwaysAllowed,
+                                      nullptr);
+    settings_service->SetLocalSetting(supervised_users::kForceSafeSearch,
+                                      nullptr);

[Marc Treib, 2017/01/16 17:24:40]

Are these changes required? Were things broken before?

[Bernhard Bauer, 2017/01/17 13:54:13]

Probably? :) The case where a profile changes from child account to regular is
not very common, so I don't think we've had good coverage for that.

What I could do is add a method that clears all local settings and call that
here -- ChildAccountService is the only instance outside of testing code where
we set local settings.

[Marc Treib, 2017/01/17 13:57:54]

Interesting ;-)
It's also possible that SU settings simply don't do anything for non-supervised
users, and so actually all these are unnecessary?
That sounds reasonable (but I'm okay either way).

+
 #if !defined(OS_CHROMEOS)
     SigninManagerFactory::GetForProfile(profile_)->ProhibitSignout(false);
 #endif