Track fraction of visits to top URLs.

chrome/browser/history/history_backend.h

Index: chrome/browser/history/history_backend.h
diff --git a/chrome/browser/history/history_backend.h b/chrome/browser/history/history_backend.h
index a55d6eb4b38e6613c2dff5c673b70e02e153a70f..8a03875970b3cefcebeb4c573da14b0b3ca25b52 100644
--- a/chrome/browser/history/history_backend.h
+++ b/chrome/browser/history/history_backend.h
@@ -909,6 +909,12 @@ class HistoryBackend : public base::RefCountedThreadSafe<HistoryBackend>,
 #if defined(OS_ANDROID)
   // Used to provide the Android ContentProvider APIs.
   scoped_ptr<AndroidProviderBackend> android_provider_backend_;
+
+  // Used to provide UMA on the number of page visits that are to the most
+  // visited URLs. This is here because the backend both has access to this
+  // information and is notified of page visits. The top sites service should
+  // be used instead whenever possible.
+  std::map<GURL, int> most_visited_urls_map_;

[jar (doing other things), 2013/06/19 00:49:58]

nit: Making this a member is good/fine.  You should make the functions that
manipulate this into methods, and then you won't need to pass it in as an
argument.

[bengr, 2013/06/19 17:44:24]

Done.

 #endif
 
   // Used to manage syncing of the typed urls datatype. This will be NULL