drive: Use ResourceMetadataStorage from FileCache

Add ResourceMetadataStorage::opened_existing_db() to trigger cache file scan at appropriate timing.

BUG=234487
TEST=unit_tests

Review URL: https://chromiumcodereview.appspot.com/17249004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@207841 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/chromeos/drive/sync_client_unittest.cc b/chrome/browser/chromeos/drive/sync_client_unittest.cc
index 60d4de9..f1fba44 100644
--- a/chrome/browser/chromeos/drive/sync_client_unittest.cc
+++ b/chrome/browser/chromeos/drive/sync_client_unittest.cc
@@ -95,7 +95,7 @@
         metadata_storage_.get(), base::MessageLoopProxy::current()));
     ASSERT_EQ(FILE_ERROR_OK, metadata_->Initialize());
 
-    cache_.reset(new FileCache(temp_dir_.path(),
+    cache_.reset(new FileCache(metadata_storage_.get(),
                                temp_dir_.path(),
                                base::MessageLoopProxy::current(),
                                NULL /* free_disk_space_getter */));
@@ -114,12 +114,6 @@
     sync_client_->set_delay_for_testing(base::TimeDelta::FromSeconds(0));
   }
 
-  virtual void TearDown() OVERRIDE {
-    sync_client_.reset();
-    cache_.reset();
-    metadata_.reset();
-  }
-
   // Adds a file to the service root and |resource_ids_|.
   void AddFileEntry(const std::string& title) {
     google_apis::GDataErrorCode error = google_apis::GDATA_FILE_ERROR;