Enable brand codes and master preferences on the Mac.

chrome/browser/mac/keystone_glue.h

Index: chrome/browser/mac/keystone_glue.h
diff --git a/chrome/browser/mac/keystone_glue.h b/chrome/browser/mac/keystone_glue.h
index 615b5e997c86586634c0d7dae73ecef22922ab86..65bdc70299d09f61b92cc13d4205ec443e6d4bef 100644
--- a/chrome/browser/mac/keystone_glue.h
+++ b/chrome/browser/mac/keystone_glue.h
@@ -198,6 +198,11 @@ enum BrandFileType {
 // Functions that may be accessed from non-Objective-C C/C++ code.
 namespace keystone_glue {
 
+// Returns the brand code of the installation. Note that beta, dev, and canary
+// channels, as well as some stable builds, may have an empty string as a brand
+// code.
+std::string BrandCode();
+
 // True if Keystone is enabled.
 bool KeystoneEnabled();