clean up LayoutTestNotificationManager overrides

BUG=

Review-Url: https://codereview.chromium.org/2682133003
Cr-Commit-Position: refs/heads/master@{#449303}

content/shell/browser/layout_test/layout_test_notification_manager.cc

@@ -4,15 +4,7 @@
 
 #include "content/shell/browser/layout_test/layout_test_notification_manager.h"
 
-#include "base/guid.h"
-#include "base/strings/nullable_string16.h"
-#include "base/strings/utf_string_conversions.h"
-#include "content/public/browser/browser_thread.h"
-#include "content/public/browser/desktop_notification_delegate.h"
-#include "content/public/browser/notification_event_dispatcher.h"
 #include "content/public/browser/permission_type.h"
-#include "content/public/common/persistent_notification_status.h"
-#include "content/public/common/platform_notification_data.h"
 #include "content/shell/browser/layout_test/layout_test_browser_context.h"
 #include "content/shell/browser/layout_test/layout_test_content_browser_client.h"
 #include "content/shell/browser/layout_test/layout_test_permission_manager.h"
@@ -22,15 +14,6 @@ namespace content {
 LayoutTestNotificationManager::LayoutTestNotificationManager() {}
 LayoutTestNotificationManager::~LayoutTestNotificationManager() {}
 
-bool LayoutTestNotificationManager::GetDisplayedNotifications(
-    BrowserContext* browser_context,
-    std::set<std::string>* displayed_notifications) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  DCHECK(displayed_notifications);
-
-  // Notifications will never outlive the lifetime of running layout tests.
-  return false;
-}
 
 blink::mojom::PermissionStatus
 LayoutTestNotificationManager::CheckPermission(const GURL& origin) {

content/shell/browser/layout_test/layout_test_notification_manager.h

@@ -25,11 +25,6 @@ class LayoutTestNotificationManager : public MockPlatformNotificationService {
   LayoutTestNotificationManager();
   ~LayoutTestNotificationManager() override;
 
-  // MockPlatformNotificationService overrides.
-  bool GetDisplayedNotifications(
-      BrowserContext* browser_context,
-      std::set<std::string>* displayed_notifications) override;
-
  private:
   blink::mojom::PermissionStatus CheckPermission(const GURL& origin) override;
   DISALLOW_COPY_AND_ASSIGN(LayoutTestNotificationManager);