[SyncFS] Migrate ServiceMetadata from MDDB to MDDBIndex.

chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc

Index: chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
diff --git a/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc b/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
index 1d88b90dac452deee730d8ddb30402ae7fc1a120..852aa46a91e297c975dae0b96d6437ad64aa0d99 100644
--- a/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
@@ -54,9 +54,12 @@ struct TrackedFile {
   TrackedFile() : should_be_absent(false), tracker_only(false) {}
 };
 
-void ExpectEquivalent(const ServiceMetadata* left,
-                      const ServiceMetadata* right) {
-  test_util::ExpectEquivalentServiceMetadata(*left, *right);
+void ExpectEquivalentServiceMetadata(
+    const MetadataDatabaseIndexInterface* left,
+    const MetadataDatabaseIndexInterface* right) {
+  EXPECT_EQ(left->GetLargestChangeID(), right->GetLargestChangeID());
+  EXPECT_EQ(left->GetSyncRootTrackerID(), right->GetSyncRootTrackerID());
+  EXPECT_EQ(left->GetNextTrackerID(), right->GetNextTrackerID());
 }
 
 void ExpectEquivalent(const FileMetadata* left, const FileMetadata* right) {
@@ -475,8 +478,8 @@ class MetadataDatabaseTest : public testing::Test {
 
     {
       SCOPED_TRACE("Expect equivalent service_metadata");
-      ExpectEquivalent(metadata_database_->service_metadata_.get(),
-                       metadata_database_2->service_metadata_.get());
+      ExpectEquivalentServiceMetadata(metadata_database_->index_.get(),
+                                      metadata_database_2->index_.get());
     }
 
     {