Add integration browser tests for settings hardening.

chrome/browser/prefs/chrome_pref_service_factory.cc

Index: chrome/browser/prefs/chrome_pref_service_factory.cc
diff --git a/chrome/browser/prefs/chrome_pref_service_factory.cc b/chrome/browser/prefs/chrome_pref_service_factory.cc
index 3f4ed9aa5af751ca66242ccb468b35e3a6dba9cd..327682568a8a0036486db968e2f06b8f4a9bff88 100644
--- a/chrome/browser/prefs/chrome_pref_service_factory.cc
+++ b/chrome/browser/prefs/chrome_pref_service_factory.cc
@@ -246,7 +246,8 @@ SettingsEnforcementGroup GetSettingsEnforcementGroup() {
 
   // Use the strongest enforcement setting in the absence of a field trial
   // config on Windows. Remember to update the OFFICIAL_BUILD section of
-  // extension_startup_browsertest.cc when updating the default value below.
+  // extension_startup_browsertest.cc and pref_hash_browsertest.cc when updating
+  // the default value below.
   // TODO(gab): Enforce this on all platforms.
   SettingsEnforcementGroup enforcement_group =
 #if defined(OS_WIN)
@@ -412,6 +413,8 @@ namespace chrome_prefs {
 
 namespace internals {
 
+// Group modifications should be reflected in first_run_browsertest.cc and
+// pref_hash_browsertest.cc.
 const char kSettingsEnforcementTrialName[] = "SettingsEnforcement";
 const char kSettingsEnforcementGroupNoEnforcement[] = "no_enforcement";
 const char kSettingsEnforcementGroupEnforceAlways[] = "enforce_always";