Adding performance tests for HQP that represent importance of optimising HistoryItemsForTerms method

components/omnibox/browser/in_memory_url_index.h

Index: components/omnibox/browser/in_memory_url_index.h
diff --git a/components/omnibox/browser/in_memory_url_index.h b/components/omnibox/browser/in_memory_url_index.h
index 3b0fa4175196156b107e88f4bfe1cb4e48103c01..a9ed88893fc58dec2653d02a64dd878fa3d80f5c 100644
--- a/components/omnibox/browser/in_memory_url_index.h
+++ b/components/omnibox/browser/in_memory_url_index.h
@@ -47,6 +47,7 @@ class InMemoryURLIndexCacheItem;
 namespace history {
 class HistoryDatabase;
 class HistoryService;
+class HQPPerfTestOnePopularURL;
 }
 
 class URLIndexPrivateData;
@@ -148,6 +149,7 @@ class InMemoryURLIndex : public KeyedService,
 
  private:
   friend class ::HistoryQuickProviderTest;
+  friend class history::HQPPerfTestOnePopularURL;
   friend class InMemoryURLIndexTest;
   friend class InMemoryURLIndexCacheTest;
   FRIEND_TEST_ALL_PREFIXES(InMemoryURLIndexTest, ExpireRow);