Add Download.IOSDownloadFileResult UMA to New Download Manager.

This is an existing histogram logged for the Old Download Manager.
The histogram is already a part of histograms.xml file.

Bug: 791806
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I93c0d84e91622654245b7dca88f06c5771e42b65
Reviewed-on: https://chromium-review.googlesource.com/973945Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545071}

ios/chrome/browser/download/download_manager_metric_names.h

@@ -22,4 +22,19 @@ enum class DownloadedFileAction {
   Count,
 };
 
+// Values of the UMA Download.IOSDownloadFileResult histogram. This action is
+// reported only for started downloads.
+enum class DownloadFileResult {
+  // Download has successfully completed.
+  Completed = 0,
+  // In progress download was cancelled by the user.
+  Cancelled = 1,
+  // Download has completed with error.
+  Failure = 2,
+  // In progress download did no finish because the tab was closed or user has
+  // quit the app.
+  Other = 3,
+  Count
+};
+
 #endif  // IOS_CHROME_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_METRIC_NAMES_H_

ios/chrome/browser/ui/download/download_manager_coordinator.mm

@@ -41,10 +41,25 @@ class UnopenedDownloadsTracker : public web::DownloadTaskObserver {
   // Stops tracking this download task.
   void Remove(web::DownloadTask* task) { task->RemoveObserver(this); }
   // DownloadTaskObserver overrides:
+  void OnDownloadUpdated(web::DownloadTask* task) override {
+    if (task->IsDone()) {
+      UMA_HISTOGRAM_ENUMERATION("Download.IOSDownloadFileResult",
+                                task->GetErrorCode()
+                                    ? DownloadFileResult::Failure
+                                    : DownloadFileResult::Completed,
+                                DownloadFileResult::Count);
+    }
+  }
   void OnDownloadDestroyed(web::DownloadTask* task) override {
     // This download task was never open by the user.
     task->RemoveObserver(this);
 
+    if (task->GetState() == web::DownloadTask::State::kInProgress) {
+      UMA_HISTOGRAM_ENUMERATION("Download.IOSDownloadFileResult",
+                                DownloadFileResult::Other,
+                                DownloadFileResult::Count);
+    }
+
     if (task->IsDone() && task->GetErrorCode() == net::OK) {
       UMA_HISTOGRAM_ENUMERATION("Download.IOSDownloadedFileAction",
                                 DownloadedFileAction::NoAction,
@@ -206,6 +221,11 @@ class UnopenedDownloadsTracker : public web::DownloadTaskObserver {
                                message:nil
                      completionHandler:^(BOOL confirmed) {
                        if (confirmed) {
+                         UMA_HISTOGRAM_ENUMERATION(
+                             "Download.IOSDownloadFileResult",
+                             DownloadFileResult::Cancelled,
+                             DownloadFileResult::Count);
+
                          [weakSelf cancelDownload];
                        }
                      }];

ios/chrome/browser/ui/download/download_manager_coordinator_unittest.mm

@@ -403,12 +403,41 @@ TEST_F(DownloadManagerCoordinatorTest, OpenIn) {
 
   // Download task is destroyed without opening the file.
   task = nullptr;
+  histogram_tester_.ExpectUniqueSample(
+      "Download.IOSDownloadFileResult",
+      static_cast<base::HistogramBase::Sample>(DownloadFileResult::Completed),
+      1);
   histogram_tester_.ExpectUniqueSample(
       "Download.IOSDownloadedFileAction",
       static_cast<base::HistogramBase::Sample>(DownloadedFileAction::NoAction),
       1);
 }
 
+// Tests destroying download task for in progress download.
+TEST_F(DownloadManagerCoordinatorTest, DestroyInProgressDownload) {
+  auto task = CreateTestTask();
+  coordinator_.downloadTask = task.get();
+  [coordinator_ start];
+
+  EXPECT_EQ(1U, base_view_controller_.childViewControllers.count);
+  DownloadManagerViewController* viewController =
+      base_view_controller_.childViewControllers.firstObject;
+  ASSERT_EQ([DownloadManagerViewController class], [viewController class]);
+
+  // Start and the download.
+  base::FilePath path;
+  ASSERT_TRUE(base::GetTempDir(&path));
+  task->Start(std::make_unique<net::URLFetcherFileWriter>(
+      base::ThreadTaskRunnerHandle::Get(), path));
+
+  // Download task is destroyed before the download is complete.
+  task = nullptr;
+  histogram_tester_.ExpectTotalCount("Download.IOSDownloadedFileAction", 0);
+  histogram_tester_.ExpectUniqueSample(
+      "Download.IOSDownloadFileResult",
+      static_cast<base::HistogramBase::Sample>(DownloadFileResult::Other), 1);
+}
+
 // Tests opening the download in Google Drive app.
 TEST_F(DownloadManagerCoordinatorTest, OpenInDrive) {
   web::FakeDownloadTask task(GURL(kTestUrl), kTestMimeType);
@@ -451,6 +480,7 @@ TEST_F(DownloadManagerCoordinatorTest, OpenInDrive) {
         willBeginSendingToApplication:kGoogleDriveAppBundleID];
   }
 
+  histogram_tester_.ExpectTotalCount("Download.IOSDownloadFileResult", 0);
   histogram_tester_.ExpectUniqueSample("Download.IOSDownloadedFileAction",
                                        static_cast<base::HistogramBase::Sample>(
                                            DownloadedFileAction::OpenedInDrive),
@@ -499,6 +529,7 @@ TEST_F(DownloadManagerCoordinatorTest, OpenInOtherApp) {
         willBeginSendingToApplication:@"foo-app-id"];
   }
 
+  histogram_tester_.ExpectTotalCount("Download.IOSDownloadFileResult", 0);
   histogram_tester_.ExpectUniqueSample(
       "Download.IOSDownloadedFileAction",
       static_cast<base::HistogramBase::Sample>(
@@ -613,10 +644,11 @@ TEST_F(DownloadManagerCoordinatorTest, StartDownload) {
 TEST_F(DownloadManagerCoordinatorTest, RetryingDownload) {
   web::FakeDownloadTask task(GURL(kTestUrl), kTestMimeType);
   task.SetSuggestedFilename(base::SysNSStringToUTF16(kTestSuggestedFileName));
-  task.SetErrorCode(net::ERR_INTERNET_DISCONNECTED);
   web::DownloadTask* task_ptr = &task;
   coordinator_.downloadTask = &task;
   [coordinator_ start];
+  task.SetErrorCode(net::ERR_INTERNET_DISCONNECTED);
+  task.SetDone(true);
 
   DownloadManagerViewController* viewController =
       base_view_controller_.childViewControllers.firstObject;
@@ -633,6 +665,9 @@ TEST_F(DownloadManagerCoordinatorTest, RetryingDownload) {
     return task_ptr->GetState() == web::DownloadTask::State::kInProgress;
   }));
 
+  histogram_tester_.ExpectUniqueSample(
+      "Download.IOSDownloadFileResult",
+      static_cast<base::HistogramBase::Sample>(DownloadFileResult::Failure), 1);
   ASSERT_EQ(1,
             user_action_tester_.GetActionCount("MobileDownloadRetryDownload"));
 }