drive: FileCache::Store marks the entry as dirty if empty MD5 is given

chrome/browser/chromeos/drive/file_cache_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chromeos/drive/file_cache.h"
 
 #include <string>
 #include <vector>
 
 #include "base/callback_helpers.h"
@@ skipping 333 matching lines @@
 
   // Store a different existing file to the same |id| but different
   // |md5|.
   md5 = "new_md5";
   TestStoreToCache(id, md5, dummy_file_path_,
                    FILE_ERROR_OK, TEST_CACHE_STATE_PRESENT);
 
   // Verify that there's only one file with name <id>, i.e. previously
   // cached file with the different md5 should be deleted.
   EXPECT_EQ(1U, CountCacheFiles(id, md5));
+
+  // Passing empty MD5 marks the entry as dirty.
+  TestStoreToCache(id, std::string(), dummy_file_path_, FILE_ERROR_OK,
+                   TEST_CACHE_STATE_PRESENT | TEST_CACHE_STATE_DIRTY);
 }
 
 TEST_F(FileCacheTestOnUIThread, RemoveFromCacheSimple) {
   std::string id("pdf:1a2b");
   std::string md5("abcdef0123456789");
   // First store a file to cache.
   TestStoreToCache(id, md5, dummy_file_path_,
                    FILE_ERROR_OK, TEST_CACHE_STATE_PRESENT);
 
   // Then try to remove existing file from cache.
@@ skipping 520 matching lines @@
   // Clear cache.
   EXPECT_TRUE(cache_->ClearAll());
 
   // Verify that the cache is removed.
   EXPECT_FALSE(cache_->GetCacheEntry(id, &cache_entry));
   EXPECT_TRUE(base::IsDirectoryEmpty(cache_files_dir_));
 }
 
 }  // namespace internal
 }  // namespace drive