Make verdict optional in csd proto.

chrome/browser/safe_browsing/download_protection_service_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/safe_browsing/download_protection_service.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <map>
@@ skipping 1061 matching lines @@
     RunLoop run_loop;
     download_service_->CheckClientDownload(
         &item, base::Bind(&DownloadProtectionServiceTest::CheckDoneCallback,
                           base::Unretained(this), run_loop.QuitClosure()));
     run_loop.Run();
     EXPECT_TRUE(IsResult(DownloadProtectionService::SAFE));
     EXPECT_TRUE(HasClientDownloadRequest());
     ClearClientDownloadRequest();
   }
   {
-    // Invalid response should result in UNKNOWN.
+    // Invalid response should result in SAFE (default value in proto).
     ClientDownloadResponse invalid_response;
     factory.SetFakeResponse(DownloadProtectionService::GetDownloadRequestUrl(),
                             invalid_response.SerializePartialAsString(),
                             net::HTTP_OK, net::URLRequestStatus::SUCCESS);
     RunLoop run_loop;
     download_service_->CheckClientDownload(
         &item, base::Bind(&DownloadProtectionServiceTest::CheckDoneCallback,
                           base::Unretained(this), run_loop.QuitClosure()));
     run_loop.Run();
-    EXPECT_TRUE(IsResult(DownloadProtectionService::UNKNOWN));
+    EXPECT_TRUE(IsResult(DownloadProtectionService::SAFE));
     EXPECT_TRUE(HasClientDownloadRequest());
     ClearClientDownloadRequest();
     EXPECT_FALSE(DownloadFeedbackService::GetPingsForDownloadForTesting(
         item, &feedback_ping, &feedback_response));
   }
   {
     // If the response is dangerous the result should also be marked as
     // dangerous.
     PrepareResponse(&factory, ClientDownloadResponse::DANGEROUS, net::HTTP_OK,
                     net::URLRequestStatus::SUCCESS);
@@ skipping 1261 matching lines @@
       &item, base::Bind(&DownloadProtectionServiceTest::CheckDoneCallback,
                         base::Unretained(this), run_loop.QuitClosure()));
   run_loop.Run();
 
   EXPECT_FALSE(HasClientDownloadRequest());
   // Overriden by flag:
   EXPECT_TRUE(IsResult(DownloadProtectionService::DANGEROUS));
 }
 
 }  // namespace safe_browsing