[tracing] Memory dump provider for leveldb_proto

components/leveldb_proto/proto_database_impl_unittest.cc

 // Copyright 2014 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 "components/leveldb_proto/proto_database_impl.h"
 
 #include <stddef.h>
 
 #include <map>
 #include <memory>
@@ skipping 469 matching lines @@
   base::RunLoop run_loop;
   db_thread.task_runner()->PostTaskAndReply(
       FROM_HERE, base::Bind(base::DoNothing), run_loop.QuitClosure());
   run_loop.Run();
 }
 
 // Test that the LevelDB properly saves entries and that load returns the saved
 // entries. If |close_after_save| is true, the database will be closed after
 // saving and then re-opened to ensure that the data is properly persisted.
 void TestLevelDBSaveAndLoad(bool close_after_save) {
+  base::MessageLoop main_loop;
+
   ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
 
   EntryMap model = GetSmallModel();
 
   KeyValueVector save_entries;
   std::vector<std::string> load_entries;
   KeyVector remove_keys;
 
   for (const auto& pair : model) {
@@ skipping 42 matching lines @@
   KeyValueVector save_entries;
   std::vector<std::string> load_entries;
   KeyVector remove_keys;
 
   EXPECT_FALSE(db->InitWithOptions(temp_dir.GetPath(), options));
   EXPECT_FALSE(db->Load(&load_entries));
   EXPECT_FALSE(db->Save(save_entries, remove_keys));
 }
 
 TEST(ProtoDatabaseImplLevelDBTest, TestMemoryDatabase) {
+  base::MessageLoop main_loop;
+
   std::unique_ptr<LevelDB> db(new LevelDB(kTestLevelDBClientName));
 
   std::vector<std::string> load_entries;
 
   ASSERT_TRUE(db->Init(base::FilePath()));
 
   ASSERT_TRUE(db->Load(&load_entries));
   EXPECT_EQ(0u, load_entries.size());
 
   KeyValueVector save_entries(1, std::make_pair("foo", "bar"));
   KeyVector remove_keys;
 
   ASSERT_TRUE(db->Save(save_entries, remove_keys));
 
   std::vector<std::string> second_load_entries;
 
   ASSERT_TRUE(db->Load(&second_load_entries));
   EXPECT_EQ(1u, second_load_entries.size());
 }
 
 }  // namespace leveldb_proto