Add a SafeSearch preference, policy and implementation.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index f74bfbe2f7757a426c3d6a138f21874704595fbe..fae7607df86bcb0221d109fa043d9ba7dc6b1e0b 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -839,6 +839,9 @@ const char kSpeechRecognitionTrayNotificationShownContexts[] =
 // Boolean controlling whether history saving is disabled.
 const char kSavingBrowserHistoryDisabled[] = "history.saving_disabled";
 
+// Boolean controlling whether SafeSearch is forced on users.

[Pam (message me for reviews), 2012/10/31 13:50:35]

Perhaps "required" or "mandatory" would be more diplomatic than "forced on
users"?

[Sergiu, 2012/11/01 18:01:52]

Renamed, but the variable name is still force_* :)

+const char kForceSafeSearch[] = "settings.force_safesearch";
+
 #if defined(TOOLKIT_GTK)
 // GTK specific preference on whether we should match the system GTK theme.
 const char kUsesSystemTheme[] = "extensions.theme.use_system";