Proof of concept implementation of context based history filtering.

chrome/browser/ui/webui/history_ui.h

Index: chrome/browser/ui/webui/history_ui.h
diff --git a/chrome/browser/ui/webui/history_ui.h b/chrome/browser/ui/webui/history_ui.h
index e7c695771f248f4a12d3c4d8e27edcf3da4f638a..c9cd58139eb76d3a6c85fde586434ccc0395ac37 100644
--- a/chrome/browser/ui/webui/history_ui.h
+++ b/chrome/browser/ui/webui/history_ui.h
@@ -47,7 +47,7 @@ class BrowsingHistoryHandler : public content::WebUIMessageHandler,
       COMBINED_ENTRY
     };
 
-    HistoryEntry(EntryType type, const GURL& url, const base::string16& title,
+    HistoryEntry(EntryType type, const GURL& url, const base::string16& title, history::HistoryContext context,
                  base::Time time, const std::string& client_id,
                  bool is_search_result, const base::string16& snippet,
                  bool blocked_visit, const std::string& accept_languages);
@@ -72,6 +72,7 @@ class BrowsingHistoryHandler : public content::WebUIMessageHandler,
 
     GURL url;
     base::string16 title;  // Title of the entry. May be empty.
+    history::HistoryContext context;
 
     // The time of the entry. Usually this will be the time of the most recent
     // visit to |url| on a particular day as defined in the local timezone.