Safety check Chrome cleaner: add C++ side metrics

* Logs the Chrome cleaner result shown to users in an UMA histogram.

Bug: 1087263
Change-Id: I25cdd664300632f3d893f59a01c3803ce3db6f86
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2332802
Commit-Queue: Rainhard Findling <rainhard@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Reviewed-by: Esmael Elmoslimany <aee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#795595}

chrome/browser/ui/webui/settings/safety_check_handler.cc

@@ -432,7 +432,11 @@ void SafetyCheckHandler::OnChromeCleanerCheckResult(
   event.SetIntKey(kNewState, static_cast<int>(status));
   event.SetStringKey(kDisplayString, GetStringForChromeCleaner(status));
   FireWebUIListener(kChromeCleanerEvent, event);
-  // TODO(crbug.com/1087263): Add metrics for the CCT result.
+  if (status != ChromeCleanerStatus::kHidden &&
+      status != ChromeCleanerStatus::kChecking) {
+    base::UmaHistogramEnumeration("Settings.SafetyCheck.ChromeCleanerResult",
+                                  status);
+  }
   chrome_cleaner_status_ = status;
   CompleteParentIfChildrenCompleted();
 }

chrome/browser/ui/webui/settings/safety_check_handler_unittest.cc

@@ -1146,11 +1146,24 @@ TEST_P(SafetyCheckHandlerChromeCleanerIdleTest, CheckChromeCleanerIdleStates) {
   safe_browsing::ChromeCleanerControllerImpl::GetInstance()->SetIdleForTesting(
       idle_reason_);
   safety_check_->PerformSafetyCheck();
+  // Ensure WebUI event is sent.
   const base::DictionaryValue* event =
       GetSafetyCheckStatusChangedWithDataIfExists(
           kChromeCleaner, static_cast<int>(expected_cct_status_));
   ASSERT_TRUE(event);
   VerifyDisplayString(event, expected_display_string_);
+  // Ensure UMA is logged.
+  if (expected_cct_status_ ==
+          SafetyCheckHandler::ChromeCleanerStatus::kHidden ||
+      expected_cct_status_ ==
+          SafetyCheckHandler::ChromeCleanerStatus::kChecking) {
+    // Hidden and checking state should not get recorded.
+    histogram_tester_.ExpectTotalCount(
+        "Settings.SafetyCheck.ChromeCleanerResult", 0);
+  } else {
+    histogram_tester_.ExpectBucketCount(
+        "Settings.SafetyCheck.ChromeCleanerResult", expected_cct_status_, 1);
+  }
 }
 
 INSTANTIATE_TEST_SUITE_P(

tools/metrics/histograms/enums.xml

@@ -61431,6 +61431,13 @@ https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_2.7.1.pdf
   <int value="4" label="NOT_SUPPORTED"/>
 </enum>
 
+<enum name="SafetyCheckChromeCleanerStatus">
+  <int value="0" label="HIDDEN"/>
+  <int value="1" label="CHECKING"/>
+  <int value="2" label="INFECTED"/>
+  <int value="3" label="REBOOT_REQUIRED"/>
+</enum>
+
 <enum name="SafetyCheckExtensionsStatus">
   <int value="0" label="CHECKING"/>
   <int value="1" label="ERROR"/>

tools/metrics/histograms/histograms.xml

@@ -161380,6 +161380,13 @@ should be kept until we remove incident reporting. -->
   </summary>
 </histogram>
 
+<histogram name="Settings.SafetyCheck.ChromeCleanerResult"
+    enum="SafetyCheckChromeCleanerStatus" expires_after="M90">
+  <owner>rainhard@chromium.org</owner>
+  <owner>msramek@chromium.org</owner>
+  <summary>Resulting state of the safety check Chrome cleaner check.</summary>
+</histogram>
+
 <histogram name="Settings.SafetyCheck.ExtensionsResult"
     enum="SafetyCheckExtensionsStatus" expires_after="M90">
   <owner>andzaytsev@google.com</owner>