Safety check Chrome cleaner: add observer only if not already added

Bug: 1087263
Change-Id: Ia59d2a208d9fcbf371ad8fd2ed59e5cdb865df64
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2507690Reviewed-by: Joe Mason <joenotcharles@chromium.org>
Reviewed-by: Esmael Elmoslimany <aee@chromium.org>
Commit-Queue: Rainhard Findling <rainhard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822641}

chrome/browser/safe_browsing/chrome_cleaner/chrome_cleaner_controller_impl_win.cc

@@ -296,6 +296,11 @@ void ChromeCleanerControllerImpl::RemoveObserver(Observer* observer) {
   observer_list_.RemoveObserver(observer);
 }
 
+bool ChromeCleanerControllerImpl::HasObserver(Observer* observer) {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  return observer_list_.HasObserver(observer);
+}
+
 void ChromeCleanerControllerImpl::OnReporterSequenceStarted() {
   DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
 

chrome/browser/safe_browsing/chrome_cleaner/chrome_cleaner_controller_impl_win.h

@@ -67,6 +67,7 @@ class ChromeCleanerControllerImpl : public ChromeCleanerController {
   void ResetIdleState() override;
   void AddObserver(Observer* observer) override;
   void RemoveObserver(Observer* observer) override;
+  bool HasObserver(Observer* observer) override;
   void OnReporterSequenceStarted() override;
   void OnReporterSequenceDone(SwReporterInvocationResult result) override;
   void RequestUserInitiatedScan(Profile* profile) override;

chrome/browser/safe_browsing/chrome_cleaner/chrome_cleaner_controller_win.h

@@ -134,6 +134,7 @@ class ChromeCleanerController {
   // by calling the corresponding |On*()| function.
   virtual void AddObserver(Observer* observer) = 0;
   virtual void RemoveObserver(Observer* observer) = 0;
+  virtual bool HasObserver(Observer* observer) = 0;
 
   // Invoked by the reporter runner, notifies the controller that a reporter
   // sequence started. If there is no pending cleaner action (currently on the

chrome/browser/safe_browsing/chrome_cleaner/mock_chrome_cleaner_controller_win.h

@@ -28,6 +28,7 @@ class MockChromeCleanerController
   MOCK_METHOD0(ResetIdleState, void());
   MOCK_METHOD1(AddObserver, void(Observer*));
   MOCK_METHOD1(RemoveObserver, void(Observer*));
+  MOCK_METHOD1(HasObserver, bool(Observer*));
   MOCK_METHOD0(OnReporterSequenceStarted, void());
   MOCK_METHOD1(OnReporterSequenceDone, void(SwReporterInvocationResult));
   MOCK_METHOD1(RequestUserInitiatedScan, void(Profile*));

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

@@ -464,9 +464,15 @@ void SafetyCheckHandler::CheckExtensions() {
 
 #if defined(OS_WIN) && BUILDFLAG(GOOGLE_CHROME_BRANDING)
 void SafetyCheckHandler::CheckChromeCleaner() {
+  if (safe_browsing::ChromeCleanerController::GetInstance()->HasObserver(
+          this)) {
+    // Observer already registered. Just fetch the current CCT status.
+    OnChromeCleanerCheckResult(fetchChromeCleanerStatus(timestamp_delegate_));
+  } else {
     // Registering the observer immediately triggers a callback with the
     // current state.
     safe_browsing::ChromeCleanerController::GetInstance()->AddObserver(this);
+  }
 }
 #endif