Updated Download.IOSDownloadedFileAction histogram value name and comments.

iOS apps are not notified if the user opened a file in Extension via
Open In.. menu. So the old metric name (No action) was not correct,
because this value was reported if the user discarded download or opened
in extension.

This CL renames the enum and histogram values to "No action or opened
via extension".

Bug: 791806
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I6eea112f9016a46a3a91d094e4dd1b1364b20c2e
Reviewed-on: https://chromium-review.googlesource.com/986714
Commit-Queue: Eugene But <eugenebut@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547523}

ios/chrome/browser/download/download_manager_metric_names.h

@@ -13,8 +13,9 @@ enum class DownloadedFileAction {
   // Downloaded file was open in the app other than Google Drive.
   OpenedInOtherApp = 1,
   // Downloaded file was discarded (the user closed the app, tab, or download
-  // manager UI).
-  NoAction = 2,
+  // manager UI) or opened via Extension (Chrome is not notified if the download
+  // was open in the extension).
+  NoActionOrOpenedViaExtension = 2,
   Count,
 };
 

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

@@ -67,9 +67,10 @@ class UnopenedDownloadsTracker : public web::DownloadTaskObserver {
     }
 
     if (task->IsDone() && task->GetErrorCode() == net::OK) {
-      UMA_HISTOGRAM_ENUMERATION("Download.IOSDownloadedFileAction",
-                                DownloadedFileAction::NoAction,
-                                DownloadedFileAction::Count);
+      UMA_HISTOGRAM_ENUMERATION(
+          "Download.IOSDownloadedFileAction",
+          DownloadedFileAction::NoActionOrOpenedViaExtension,
+          DownloadedFileAction::Count);
     }
   }
 };

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

@@ -418,7 +418,8 @@ TEST_F(DownloadManagerCoordinatorTest, OpenIn) {
       1);
   histogram_tester_.ExpectUniqueSample(
       "Download.IOSDownloadedFileAction",
-      static_cast<base::HistogramBase::Sample>(DownloadedFileAction::NoAction),
+      static_cast<base::HistogramBase::Sample>(
+          DownloadedFileAction::NoActionOrOpenedViaExtension),
       1);
 }
 

tools/metrics/histograms/enums.xml

@@ -9983,7 +9983,7 @@ Called by update_net_error_codes.py.-->
 <enum name="DownloadedFileAction">
   <int value="0" label="Opened in Drive"/>
   <int value="1" label="Opened in another app"/>
-  <int value="2" label="No action"/>
+  <int value="2" label="No action or opened via extension"/>
 </enum>
 
 <enum name="DownloadFilePickerResult">