Add help button to app launcher

chrome/common/url_constants.h

Index: chrome/common/url_constants.h
diff --git a/chrome/common/url_constants.h b/chrome/common/url_constants.h
index a58576e41d0a89d9b6fdd5476717bacab9889dde..4dc273cb6508102b919741d4e467ebe734b1c685 100644
--- a/chrome/common/url_constants.h
+++ b/chrome/common/url_constants.h
@@ -374,6 +374,9 @@ extern const char kSyncEverythingLearnMoreURL[];
 // The URL for information on how to recover your password.
 extern const char kInvalidPasswordHelpURL[];
 
+// The URL for information on how to use the app launcher.
+extern const char kAppLauncherHelpURL[];
+
 // The URL for information on what to do if you can't sign in to your Google
 // account.
 extern const char kCanNotAccessAccountURL[];