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

chrome/common/extensions/extension_constants.cc

Index: chrome/common/extensions/extension_constants.cc
diff --git a/chrome/common/extensions/extension_constants.cc b/chrome/common/extensions/extension_constants.cc
index 68288019e8977694bfc7766b71895300a7ee20aa..72b2feea6fa80f7e7a1d29eba147ccc42fa5a727 100644
--- a/chrome/common/extensions/extension_constants.cc
+++ b/chrome/common/extensions/extension_constants.cc
@@ -30,6 +30,7 @@ namespace extension_misc {
 const char kBookmarkManagerId[] = "eemcgdkfndhakfknompkggombfjjjeno";
 const char kChromeAppId[] = "mgndgikekgjfcpckkfioiadnlibdjbkf";
 const char kCloudPrintAppId[] = "mfehgcgbbipciphmccgaenjidiccnmng";
+const char kDataSaverExtensionId[] = "pfmgfdlgomnbgkofeojodiodmgpgmkac";
 const char kEasyUnlockAppId[] = "mkaemigholebcgchlkbankmihknojeak";
 const char kEnterpriseWebStoreAppId[] = "afchcafgojfnemjkcbhfekplkmjaldaa";
 const char kGmailAppId[] = "pjkljhegncpnkpknbcohdijeoejaedia";