Fix attempt number for multi payload.

VerifyPayload() is called for every payload, so we shouldn't call
DownloadComplete() in there, move it to DownloadAction after all
payloads are applied.

Bug: 74980927
Test: check UpdateEngine.SuccessfulUpdate.AttemptCount in log
Test: update_engine_unittests
Change-Id: Iddb0ab111a7893f0c7bbf7a5119bd517ac5410a7
diff --git a/payload_consumer/download_action.cc b/payload_consumer/download_action.cc
index f1b6e33..4d46d4f 100644
--- a/payload_consumer/download_action.cc
+++ b/payload_consumer/download_action.cc
@@ -387,8 +387,13 @@
         StartDownloading();
         return;
       }
+
+      // All payloads have been applied and verified.
+      if (delegate_)
+        delegate_->DownloadComplete();
+
       // Log UpdateEngine.DownloadAction.* histograms to help diagnose
-      // long-blocking oeprations.
+      // long-blocking operations.
       std::string histogram_output;
       base::StatisticsRecorder::WriteGraph(
           "UpdateEngine.DownloadAction.", &histogram_output);