Add EmitSequenceData stub to FakeCowWriter

Bug: 177104308
Test: Compiles
Change-Id: I9f6427a675c0676650a08d8a0cb46b1abda2c305
diff --git a/payload_consumer/snapshot_extent_writer_unittest.cc b/payload_consumer/snapshot_extent_writer_unittest.cc
index 2201043..51672ca 100644
--- a/payload_consumer/snapshot_extent_writer_unittest.cc
+++ b/payload_consumer/snapshot_extent_writer_unittest.cc
@@ -70,6 +70,10 @@
     return true;
   }
 
+  bool EmitSequenceData(size_t num_ops, const uint32_t* data) override {
+    return false;
+  }
+
   // Return number of bytes the cow image occupies on disk.
   uint64_t GetCowSize() override {
     return std::accumulate(