When the user navigates to the home page, make sure to set the RLZ string

content/common/page_transition_types.h

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_COMMON_PAGE_TRANSITION_TYPES_H_
 #define CONTENT_COMMON_PAGE_TRANSITION_TYPES_H_
 #pragma once
 
 #include "base/basictypes.h"
 
@@ skipping 87 matching lines @@
     LAST_CORE = KEYWORD_GENERATED,
     CORE_MASK = 0xFF,
 
     // Qualifiers
     // Any of the core values above can be augmented by one or more qualifiers.
     // These qualifiers further define the transition.
 
     // User used the Forward or Back button to navigate among browsing history.
     FORWARD_BACK = 0x01000000,
 
+    // User is navigating to the home page.
+    HOME_PAGE = 0x02000000,
+
     // The beginning of a navigation chain.
     CHAIN_START = 0x10000000,
 
     // The last transition in a redirect chain.
     CHAIN_END = 0x20000000,
 
     // Redirects caused by JavaScript or a meta refresh tag on the page.
     CLIENT_REDIRECT = 0x40000000,
 
     // Redirects sent from the server by HTTP headers. It might be nice to
@@ skipping 38 matching lines @@
   // Return the qualifier
   static int32 GetQualifier(Type type) {
     return type & QUALIFIER_MASK;
   }
 
   // Return a string version of the core type values.
   static const char* CoreTransitionString(Type type);
 };
 
 #endif  // CONTENT_COMMON_PAGE_TRANSITION_TYPES_H_