[Sync] Add interface and backend impl for typed URL syncable service

chrome/browser/history/expire_history_backend_unittest.cc

Index: chrome/browser/history/expire_history_backend_unittest.cc
diff --git a/chrome/browser/history/expire_history_backend_unittest.cc b/chrome/browser/history/expire_history_backend_unittest.cc
index 712b792adee68cb06fed1a509593f8add06355c6..9ea660932e6c246cfe753f5618f411507b5a406c 100644
--- a/chrome/browser/history/expire_history_backend_unittest.cc
+++ b/chrome/browser/history/expire_history_backend_unittest.cc
@@ -179,6 +179,10 @@ class ExpireHistoryTest : public testing::Test,
     // store them so we can tell that the correct notifications were sent.
     notifications_.push_back(std::make_pair(type, details_deleted));
   }
+  virtual void NotifySyncURLsDeleted(
+      bool all_history,
+      bool archived,
+      URLRows* rows) OVERRIDE {}
 };
 
 // The example data consists of 4 visits. The middle two visits are to the