win: Fix debug iterator failure on empty database read/write

client/crash_report_database_test.cc

 // Copyright 2015 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 537 matching lines @@
             db()->LookUpCrashReport(delete_completed.uuid, &delete_completed));
   EXPECT_EQ(CrashReportDatabase::kReportNotFound,
             db()->DeleteReport(delete_completed.uuid));
 
   EXPECT_EQ(CrashReportDatabase::kNoError,
             db()->LookUpCrashReport(keep_pending.uuid, &keep_pending));
   EXPECT_EQ(CrashReportDatabase::kNoError,
             db()->LookUpCrashReport(keep_completed.uuid, &keep_completed));
 }
 
+TEST_F(CrashReportDatabaseTest, DeleteReportEmptyingDatabase) {
+  CrashReportDatabase::Report report;
+  CreateCrashReport(&report);
+
+  EXPECT_TRUE(FileExists(report.file_path));
+
+  UploadReport(report.uuid, true, "1");
+
+  EXPECT_EQ(CrashReportDatabase::kNoError,
+            db()->LookUpCrashReport(report.uuid, &report));
+
+  EXPECT_TRUE(FileExists(report.file_path));
+
+  // This causes an empty database to be written, make sure this is handled.
+  EXPECT_EQ(CrashReportDatabase::kNoError, db()->DeleteReport(report.uuid));
+  EXPECT_FALSE(FileExists(report.file_path));
+}
+
+TEST_F(CrashReportDatabaseTest, ReadEmptyDatabase) {
+  CrashReportDatabase::Report report;
+  CreateCrashReport(&report);
+  EXPECT_EQ(CrashReportDatabase::kNoError, db()->DeleteReport(report.uuid));
+
+  // Deleting and the creating another report causes an empty database to be
+  // loaded. Make sure this is handled.
+
+  CrashReportDatabase::Report report2;
+  CreateCrashReport(&report2);
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace crashpad