Fix long unit tests in DownloadProtectionServiceTest

We had a few tests that wanted to inspect the ClientDownloadRequest,
but didn't do anything with the TestURLLoaderFactory. This led to the
test waiting for 7 seconds, until the timeout kicks in. This CL adds
calls to PrepareResponse, to mock out the network response, so that
we no longer wait for a timeout. All unit tests under
DownloadProtectionServiceTest now take <1s, with the worst around 200ms.

Bug: 896796
Change-Id: I1c8f24c962fbb5d13e2a86ecfda6f80c1d19d1f4
Reviewed-on: https://chromium-review.googlesource.com/c/1299502Reviewed-by: Nathan Parker <nparker@chromium.org>
Commit-Queue: Daniel Rubery <drubery@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603511}

chrome/browser/safe_browsing/download_protection/check_client_download_request.cc

@@ -190,7 +190,6 @@ void CheckClientDownloadRequest::Cancel(bool download_destroyed) {
 void CheckClientDownloadRequest::OnDownloadDestroyed(
     download::DownloadItem* download) {
   Cancel(/*download_destroyed=*/true);
-  DCHECK(item_ == NULL);
 }
 
 // TODO: this method puts "DownloadProtectionService::" in front of a lot of

chrome/browser/safe_browsing/download_protection/download_protection_service_unittest.cc

@@ -1755,6 +1755,10 @@ TEST_F(DownloadProtectionServiceTest, CheckClientDownloadValidateRequest) {
                   tmp_path_, BinaryFeatureExtractor::kDefaultOptions, _, _))
       .WillOnce(SetDosHeaderContents("dummy dos header"));
 #endif  // OS_MACOSX
+
+  PrepareResponse(ClientDownloadResponse::SAFE, net::HTTP_OK,
+                  net::URLRequestStatus::SUCCESS);
+
   RunLoop run_loop;
   download_service_->CheckClientDownload(
       &item, base::Bind(&DownloadProtectionServiceTest::CheckDoneCallback,
@@ -1828,6 +1832,9 @@ TEST_F(DownloadProtectionServiceTest,
                   tmp_path_, BinaryFeatureExtractor::kDefaultOptions, _, _));
 #endif  // OS_MACOSX
 
+  PrepareResponse(ClientDownloadResponse::SAFE, net::HTTP_OK,
+                  net::URLRequestStatus::SUCCESS);
+
   RunLoop run_loop;
   download_service_->CheckClientDownload(
       &item, base::Bind(&DownloadProtectionServiceTest::CheckDoneCallback,
@@ -1896,6 +1903,9 @@ TEST_F(DownloadProtectionServiceTest,
                 interceptor_run_loop.Quit();
             }));
 
+    PrepareResponse(ClientDownloadResponse::SAFE, net::HTTP_OK,
+                    net::URLRequestStatus::SUCCESS);
+
     RunLoop run_loop;
     download_service_->CheckClientDownload(
         &item, base::Bind(&DownloadProtectionServiceTest::CheckDoneCallback,
@@ -1964,6 +1974,9 @@ TEST_F(DownloadProtectionServiceTest,
                   reinterpret_cast<history::ContextID>(1), 0, GURL(), redirects,
                   ui::PAGE_TRANSITION_TYPED, history::SOURCE_BROWSED, false);
 
+    PrepareResponse(ClientDownloadResponse::SAFE, net::HTTP_OK,
+                    net::URLRequestStatus::SUCCESS);
+
     RunLoop run_loop;
     download_service_->CheckClientDownload(
         &item, base::Bind(&DownloadProtectionServiceTest::CheckDoneCallback,