Move InMemoryURLIndex Caching Operations to FILE Thread

chrome/browser/history/history_backend.h

Index: chrome/browser/history/history_backend.h
===================================================================
--- chrome/browser/history/history_backend.h	(revision 117518)
+++ chrome/browser/history/history_backend.h	(working copy)
@@ -12,6 +12,7 @@
 #include "base/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/mru_cache.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/cancelable_request.h"
 #include "chrome/browser/history/archived_database.h"
@@ -19,6 +20,7 @@
 #include "chrome/browser/history/history_database.h"
 #include "chrome/browser/history/history_marshaling.h"
 #include "chrome/browser/history/history_types.h"
+#include "chrome/browser/history/in_memory_url_index.h"
 #include "chrome/browser/history/text_database_manager.h"
 #include "chrome/browser/history/thumbnail_database.h"
 #include "chrome/browser/history/visit_tracker.h"
@@ -27,6 +29,7 @@
 
 class BookmarkService;
 struct DownloadPersistentStoreInfo;
+class Profile;
 class TestingProfile;
 struct ThumbnailScore;
 
@@ -104,7 +107,8 @@
   // may be NULL.
   //
   // This constructor is fast and does no I/O, so can be called at any time.
-  HistoryBackend(const FilePath& history_dir,
+  HistoryBackend(Profile* profile,
+                 const FilePath& history_dir,
                  int id,
                  Delegate* delegate,
                  BookmarkService* bookmark_service);
@@ -259,6 +263,13 @@
                               const base::Time remove_end);
   void RemoveDownloads(const base::Time remove_end);
 
+  // InMemoryURLIndex ----------------------------------------------------------
+
+  // Returns the quick history index.
+  history::InMemoryURLIndex* InMemoryIndex() const {
+    return in_memory_url_index_.get();
+  }
+
   // Segment usage -------------------------------------------------------------
 
   void QuerySegmentUsage(scoped_refptr<QuerySegmentUsageRequest> request,
@@ -583,6 +594,9 @@
   // created.
   scoped_ptr<TextDatabaseManager> text_database_;
 
+  // The index used for quick history lookups.
+  scoped_refptr<history::InMemoryURLIndex> in_memory_url_index_;
+
   // Manages expiration between the various databases.
   ExpireHistoryBackend expirer_;