bookmarks: Remove in_memory_database.h include, it's unused.

chrome/browser/bookmarks/bookmark_index_unittest.cc

Index: chrome/browser/bookmarks/bookmark_index_unittest.cc
diff --git a/chrome/browser/bookmarks/bookmark_index_unittest.cc b/chrome/browser/bookmarks/bookmark_index_unittest.cc
index 2b1e8a7c8a0d40841abbb5ce521d4de898b78327..f9ae84ed51fcca669af2a6dc206e9298c4d000f8 100644
--- a/chrome/browser/bookmarks/bookmark_index_unittest.cc
+++ b/chrome/browser/bookmarks/bookmark_index_unittest.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "chrome/browser/bookmarks/bookmark_index.h"
+
 #include <string>
 #include <vector>
 
@@ -10,13 +12,11 @@
 #include "base/string_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/utf_string_conversions.h"
-#include "chrome/browser/bookmarks/bookmark_index.h"
 #include "chrome/browser/bookmarks/bookmark_model.h"
 #include "chrome/browser/bookmarks/bookmark_model_factory.h"
 #include "chrome/browser/bookmarks/bookmark_utils.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
-#include "chrome/browser/history/in_memory_database.h"
 #include "chrome/browser/history/url_database.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/public/test/test_browser_thread.h"