Handle the case where Purge is called while upload is in progress.

components/ukm/ukm_service_unittest.cc

Index: components/ukm/ukm_service_unittest.cc
diff --git a/components/ukm/ukm_service_unittest.cc b/components/ukm/ukm_service_unittest.cc
index be8090c2724d565c99244ac3a32f7e02d4cc14bd..120657fa74d1081106e1ea880b3802b936c84f89 100644
--- a/components/ukm/ukm_service_unittest.cc
+++ b/components/ukm/ukm_service_unittest.cc
@@ -188,4 +188,23 @@ TEST_F(UkmServiceTest, LogsUploadedWithSourcesOnly) {
   EXPECT_EQ(GetPersistedLogCount(), 1);
 }
 
+TEST_F(UkmServiceTest, PurgeMidUpload) {
+  UkmService service(&prefs_, &client_);
+  EXPECT_EQ(GetPersistedLogCount(), 0);
+  service.Initialize();
+  task_runner_->RunUntilIdle();
+  service.EnableRecording();
+  service.EnableReporting();
+  service.RecordSource(MakeSource("https://google.com", 300));
+  // Should init, generate a log, and start an upload.
+  task_runner_->RunPendingTasks();
+  EXPECT_TRUE(client_.uploader()->is_uploading());
+  // Purge should delete all logs, including the one being sent.
+  service.Purge();
+  // Upload succeeds after logs was deleted.
+  client_.uploader()->CompleteUpload(200);
+  EXPECT_EQ(GetPersistedLogCount(), 0);
+  EXPECT_FALSE(client_.uploader()->is_uploading());
+}
+
 }  // namespace ukm