Make HistoryDatabase own StarredURLDatabase instead of inheriting from it.

chrome/browser/history/starred_url_database.cc

Index: chrome/browser/history/starred_url_database.cc
diff --git a/chrome/browser/history/starred_url_database.cc b/chrome/browser/history/starred_url_database.cc
index 12d5857f8d8b17919659fdcc32f43e25c888a223..166e20cb6fddf5431bf6a31f7031029846399e14 100644
--- a/chrome/browser/history/starred_url_database.cc
+++ b/chrome/browser/history/starred_url_database.cc
@@ -118,7 +118,8 @@ void ResetBookmarkNode(const history::StarredEntry& entry,
 // static
 const int64 StarredURLDatabase::kBookmarkBarID = 1;
 
-StarredURLDatabase::StarredURLDatabase() {
+StarredURLDatabase::StarredURLDatabase(sql::Connection* db)
+    : db_(db) {
 }
 
 StarredURLDatabase::~StarredURLDatabase() {
@@ -166,6 +167,10 @@ bool StarredURLDatabase::GetAllStarredEntries(
   return true;
 }
 
+sql::Connection& StarredURLDatabase::GetDB() {
+  return *db_;
+}
+
 bool StarredURLDatabase::EnsureStarredIntegrity() {
   std::set<StarredNode*> roots;
   std::set<StarID> folders_with_duplicate_ids;