Retire ScopedObserver in chrome/browser/ui/webui.

ScopedObserver is being deprecated in favor of two new classes:
- base::ScopedObservation for observers that only ever observe
  a single source.
- base::ScopedMultiSourceObservation for observers that do or may
  observe more than a single source.

Tbr: [email protected]
Bug: 1145565
Change-Id: I8a6c5867c2bc5e073245e1ee82aed43d44b47632
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2611553
Reviewed-by: Sigurður Ásgeirsson <[email protected]>
Reviewed-by: François Doray <[email protected]>
Commit-Queue: Sigurður Ásgeirsson <[email protected]>
Cr-Commit-Position: refs/heads/master@{#841126}
diff --git a/chrome/browser/ui/webui/components/components_handler.h b/chrome/browser/ui/webui/components/components_handler.h
index 5ed5d43..4f2f38f 100644
--- a/chrome/browser/ui/webui/components/components_handler.h
+++ b/chrome/browser/ui/webui/components/components_handler.h
@@ -8,7 +8,7 @@
 #include <memory>
 #include <string>
 
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "base/strings/string16.h"
 #include "components/component_updater/component_updater_service.h"
 #include "components/update_client/update_client.h"
@@ -53,9 +53,9 @@
   // Weak pointer; injected for testing.
   component_updater::ComponentUpdateService* const component_updater_;
 
-  ScopedObserver<component_updater::ComponentUpdateService,
-                 component_updater::ComponentUpdateService::Observer>
-      observer_{this};
+  base::ScopedObservation<component_updater::ComponentUpdateService,
+                          component_updater::ComponentUpdateService::Observer>
+      observation_{this};
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_COMPONENTS_COMPONENTS_HANDLER_H_