Initial CL for Data Saver (Flywheel) prompt when cellular network detected

chromeos/chromeos_switches.cc

Index: chromeos/chromeos_switches.cc
diff --git a/chromeos/chromeos_switches.cc b/chromeos/chromeos_switches.cc
index 6f4e4a7e46f320e5e9a8d4a5b073a186c7927e24..b86efb19ad06273af9a4c04ec11c44318799a2cf 100644
--- a/chromeos/chromeos_switches.cc
+++ b/chromeos/chromeos_switches.cc
@@ -345,6 +345,11 @@ const char kEnableFirewallHolePunching[] = "enable-firewall-hole-punching";
 // handle the plugged in printer.
 const char kEnablePrinterAppSearch[] = "enable-printer-app-search";
 
+// Switches and optional value for Data Saver prompt on cellular networks.
+const char kDisableDataSaverPrompt[] = "disable-datasaver-prompt";
+const char kEnableDataSaverPrompt[] = "enable-datasaver-prompt";
+const char kDataSaverPromptDemoMode[] = "demo";
+
 bool WakeOnWifiEnabled() {
   return !base::CommandLine::ForCurrentProcess()->HasSwitch(kDisableWakeOnWifi);
 }