[WebOTP] Deflake SmsBrowserTest.RecordUserCancelledAsOutcome

This patch first splits the test into two to test UMA / UKM separately.

For UMA test, it
  - adds a run loop to make sure the JavaScript has been executed.
  - adds a call to |FetchHistogramsFromChildProcesses| to make sure that
  the necessary render process could be initialized before fetching the
  histograms. crrev.com/c/1804574 updated the functionality of this
  helper function.

Bug: 1141862
Change-Id: Id119b2b01d0f46faab56cd0739e78a5fbeadf2c7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2566250
Commit-Queue: Yi Gu <yigu@chromium.org>
Reviewed-by: Majid Valipour <majidvp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#832537}

content/browser/sms/sms_browsertest.cc

@@ -915,7 +915,7 @@ IN_PROC_BROWSER_TEST_F(SmsBrowserTest,
   ExpectNoOutcomeUKM();
 }
 
-IN_PROC_BROWSER_TEST_F(SmsBrowserTest, RecordUserCancelledAsOutcome) {
+IN_PROC_BROWSER_TEST_F(SmsBrowserTest, RecordUserCancelledAsOutcomeUKM) {
   base::HistogramTester histogram_tester;
   base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
       switches::kWebOtpBackend, switches::kWebOtpBackendUserConsent);
@@ -949,6 +949,34 @@ IN_PROC_BROWSER_TEST_F(SmsBrowserTest, RecordUserCancelledAsOutcome) {
   content::FetchHistogramsFromChildProcesses();
   ExpectOutcomeUKM(url, blink::WebOTPServiceOutcome::kUserCancelled);
   ExpectTimingUKM("TimeUserCancelMs");
+}
+
+IN_PROC_BROWSER_TEST_F(SmsBrowserTest, RecordUserCancelledAsOutcomeUMA) {
+  base::HistogramTester histogram_tester;
+  GURL url = GetTestUrl(nullptr, "simple_page.html");
+  EXPECT_TRUE(NavigateToURL(shell(), url));
+
+  auto provider = std::make_unique<MockSmsProvider>();
+  MockSmsProvider* mock_provider_ptr = provider.get();
+  BrowserMainLoop::GetInstance()->SetSmsProviderForTesting(std::move(provider));
+
+  shell()->web_contents()->SetDelegate(&delegate_);
+
+  base::RunLoop loop;
+  EXPECT_CALL(*mock_provider_ptr, Retrieve(_)).WillOnce(Invoke([&]() {
+    mock_provider_ptr->NotifyFailure(FailureType::kPromptCancelled);
+    loop.Quit();
+  }));
+
+  EXPECT_TRUE(ExecJs(shell(), R"(
+       navigator.credentials.get({otp: {transport: ["sms"]}});
+     )"));
+  // Makes sure that all the renderer processes are initialized before recording
+  // and fetching the histograms.
+  FetchHistogramsFromChildProcesses();
+  loop.Run();
+
+  FetchHistogramsFromChildProcesses();
   histogram_tester.ExpectTotalCount("Blink.Sms.Receive.TimeUserCancel", 1);
 }