Retire ScopedObserver in /components/subresource_filter.

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.

This CL was uploaded by git cl split.

R=jkarlin@chromium.org

Bug: 1145565
Change-Id: Id5414833dd0227489e629f56ea4a94a7ad86df58
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2533023
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Auto-Submit: Sigurður Ásgeirsson <siggi@chromium.org>
Reviewed-by: Josh Karlin <jkarlin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826433}

components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.cc

@@ -131,7 +131,7 @@ ContentSubresourceFilterThrottleManager::
       dealer_handle_(dealer_handle),
       client_(std::move(client)) {
   SubresourceFilterObserverManager::CreateForWebContents(web_contents);
-  scoped_observer_.Add(
+  scoped_observation_.Observe(
       SubresourceFilterObserverManager::FromWebContents(web_contents));
 }
 
@@ -141,7 +141,7 @@ ContentSubresourceFilterThrottleManager::
 void ContentSubresourceFilterThrottleManager::OnSubresourceFilterGoingAway() {
   // Stop observing here because the observer manager could be destroyed by the
   // time this class is destroyed.
-  scoped_observer_.RemoveAll();
+  scoped_observation_.RemoveObservation();
 }
 
 void ContentSubresourceFilterThrottleManager::RenderFrameDeleted(

components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.h

@@ -13,7 +13,7 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/optional.h"
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "base/stl_util.h"
 #include "base/supports_user_data.h"
 #include "components/subresource_filter/content/browser/subframe_navigation_filtering_throttle.h"
@@ -272,8 +272,9 @@ class ContentSubresourceFilterThrottleManager
 
   content::WebContentsFrameReceiverSet<mojom::SubresourceFilterHost> receiver_;
 
-  ScopedObserver<SubresourceFilterObserverManager, SubresourceFilterObserver>
-      scoped_observer_{this};
+  base::ScopedObservation<SubresourceFilterObserverManager,
+                          SubresourceFilterObserver>
+      scoped_observation_{this};
 
   // Lazily instantiated in EnsureRulesetHandle when the first page level
   // activation is triggered. Will go away when there are no more activated

components/subresource_filter/content/browser/subresource_filter_observer_test_utils.cc

@@ -12,19 +12,18 @@
 namespace subresource_filter {
 
 TestSubresourceFilterObserver::TestSubresourceFilterObserver(
-    content::WebContents* web_contents)
-    : scoped_observer_(this) {
+    content::WebContents* web_contents) {
   auto* manager =
       SubresourceFilterObserverManager::FromWebContents(web_contents);
   DCHECK(manager);
-  scoped_observer_.Add(manager);
+  scoped_observation_.Observe(manager);
   Observe(web_contents);
 }
 
 TestSubresourceFilterObserver::~TestSubresourceFilterObserver() {}
 
 void TestSubresourceFilterObserver::OnSubresourceFilterGoingAway() {
-  scoped_observer_.RemoveAll();
+  scoped_observation_.RemoveObservation();
 }
 
 void TestSubresourceFilterObserver::OnPageActivationComputed(

components/subresource_filter/content/browser/subresource_filter_observer_test_utils.h

@@ -10,7 +10,7 @@
 
 #include "base/macros.h"
 #include "base/optional.h"
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "components/safe_browsing/core/db/util.h"
 #include "components/safe_browsing/core/db/v4_protocol_manager_util.h"
 #include "components/subresource_filter/content/browser/subresource_filter_observer.h"
@@ -74,8 +74,9 @@ class TestSubresourceFilterObserver : public SubresourceFilterObserver,
       pending_activations_;
   base::Optional<mojom::ActivationLevel> last_committed_activation_;
 
-  ScopedObserver<SubresourceFilterObserverManager, SubresourceFilterObserver>
-      scoped_observer_;
+  base::ScopedObservation<SubresourceFilterObserverManager,
+                          SubresourceFilterObserver>
+      scoped_observation_{this};
   DISALLOW_COPY_AND_ASSIGN(TestSubresourceFilterObserver);
 };