Implement support for disabling sync through configuration management.

chrome/browser/profile.h

Index: chrome/browser/profile.h
diff --git a/chrome/browser/profile.h b/chrome/browser/profile.h
index e462b6c225507dd437e5236efc3dd1d3f02cde6c..e0837cd08ed50b89e3804e016da4600dbea0d6ec 100644
--- a/chrome/browser/profile.h
+++ b/chrome/browser/profile.h
@@ -448,6 +448,10 @@ class Profile {
     return 0 == accessibility_pause_level_;
   }
 
+  // Checks whether sync is configurable by the user. Returns false if sync is
+  // disabled or controlled by configuration management.
+  bool IsSyncAccessible();
+
  protected:
   static URLRequestContextGetter* default_request_context_;