[WebOTP] Report SMSReceiverStart in Blink.UseCounter.Features

We no longer report after crrev.com/c/2097041. This patch resumes the
reporting logic.

Bug: 1107590
Change-Id: I9dd8d30a91f48077694a6a3d054f36aa9b259868
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2350093Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Reviewed-by: Sam Goto <goto@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797214}

content/browser/sms/sms_browsertest.cc

@@ -720,4 +720,34 @@ IN_PROC_BROWSER_TEST_F(SmsBrowserTest, SmsFetcherUAF) {
   navigate.Run();
 }
 
+IN_PROC_BROWSER_TEST_F(SmsBrowserTest, ReportSMSReceiverStartInUseCounter) {
+  GURL url = GetTestUrl(nullptr, "simple_page.html");
+  EXPECT_TRUE(NavigateToURL(shell(), url));
+
+  shell()->web_contents()->SetDelegate(&delegate_);
+
+  ExpectSmsPrompt();
+  auto provider = std::make_unique<MockSmsProvider>();
+  MockSmsProvider* mock_provider_ptr = provider.get();
+  BrowserMainLoop::GetInstance()->SetSmsProviderForTesting(std::move(provider));
+
+  EXPECT_CALL(*mock_provider_ptr, Retrieve(_)).WillOnce(Invoke([&]() {
+    mock_provider_ptr->NotifyReceive(url::Origin::Create(url), "hello");
+    ConfirmPrompt();
+  }));
+  base::HistogramTester histogram_tester;
+  std::string script = R"(
+    (async () => {
+      let cred = await navigator.credentials.get({otp: {transport: ["sms"]}});
+      return cred.code;
+    }) ();
+  )";
+  EXPECT_EQ("hello", EvalJs(shell(), script));
+
+  content::FetchHistogramsFromChildProcesses();
+  histogram_tester.ExpectBucketCount(
+      "Blink.UseCounter.Features", blink::mojom::WebFeature::kSMSReceiverStart,
+      1);
+}
+
 }  // namespace content

third_party/blink/renderer/modules/credentialmanager/credentials_container.cc

@@ -7,6 +7,7 @@
 #include <memory>
 #include <utility>
 
+#include "base/metrics/histogram_macros.h"
 #include "build/build_config.h"
 #include "third_party/blink/public/common/sms/sms_receiver_outcome.h"
 #include "third_party/blink/public/mojom/credentialmanager/credential_manager.mojom-blink.h"
@@ -654,6 +655,8 @@ ScriptPromise CredentialsContainer::get(
         CredentialManagerProxy::From(script_state)->SmsReceiver();
     sms_receiver->Receive(WTF::Bind(&OnSmsReceive, WrapPersistent(resolver),
                                     base::TimeTicks::Now()));
+    UMA_HISTOGRAM_ENUMERATION("Blink.UseCounter.Features",
+                              WebFeature::kSMSReceiverStart);
     return promise;
   }