Fix WeakPtrFactory member ordering in chrome/browser

chrome/browser/history/expire_history_backend.h

Index: chrome/browser/history/expire_history_backend.h
diff --git a/chrome/browser/history/expire_history_backend.h b/chrome/browser/history/expire_history_backend.h
index fdabd77095b98a74d9c88fe51d03113dfb6405eb..3cb8e806ef83304067c3335e275d3a51a1270191 100644
--- a/chrome/browser/history/expire_history_backend.h
+++ b/chrome/browser/history/expire_history_backend.h
@@ -253,10 +253,6 @@ class ExpireHistoryBackend {
   HistoryDatabase* main_db_;       // Main history database.
   ThumbnailDatabase* thumb_db_;    // Thumbnails and favicons.
 
-  // Used to generate runnable methods to do timers on this class. They will be
-  // automatically canceled when this class is deleted.
-  base::WeakPtrFactory<ExpireHistoryBackend> weak_factory_;
-
   // The threshold for "old" history where we will automatically delete it.
   base::TimeDelta expiration_threshold_;
 
@@ -281,6 +277,10 @@ class ExpireHistoryBackend {
   // loaded before returning.
   HistoryClient* history_client_;
 
+  // Used to generate runnable methods to do timers on this class. They will be
+  // automatically canceled when this class is deleted.
+  base::WeakPtrFactory<ExpireHistoryBackend> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(ExpireHistoryBackend);
 };