diff --git a/chromium/components/dom_distiller/core/task_tracker.cc b/chromium/components/dom_distiller/core/task_tracker.cc
index e66a62c4091e..f22c88967bc7 100644
--- a/chromium/components/dom_distiller/core/task_tracker.cc
+++ b/chromium/components/dom_distiller/core/task_tracker.cc
@@ -85,7 +85,7 @@ void TaskTracker::AddSaveCallback(SaveCallback callback) {
 
 std::unique_ptr<ViewerHandle> TaskTracker::AddViewer(
     ViewRequestDelegate* delegate) {
-  viewers_.push_back(delegate);
+  viewers_.AddObserver(delegate);
   if (content_ready_) {
     // Distillation for this task has already completed, and so the delegate can
     // be immediately told of the result.
@@ -115,7 +115,7 @@ bool TaskTracker::HasUrl(const GURL& url) const {
 }
 
 void TaskTracker::RemoveViewer(ViewRequestDelegate* delegate) {
-  base::Erase(viewers_, delegate);
+  viewers_.RemoveObserver(delegate);
   if (viewers_.empty()) {
     MaybeCancel();
   }
@@ -219,8 +219,8 @@ void TaskTracker::DistilledArticleReady(
 }
 
 void TaskTracker::NotifyViewersAndCallbacks() {
-  for (auto* viewer : viewers_) {
-    NotifyViewer(viewer);
+  for (auto& viewer : viewers_) {
+    NotifyViewer(&viewer);
   }
 
   // Already inside a callback run SaveCallbacks directly.
@@ -242,8 +242,8 @@ void TaskTracker::DoSaveCallbacks(bool success) {
 
 void TaskTracker::OnArticleDistillationUpdated(
     const ArticleDistillationUpdate& article_update) {
-  for (auto* viewer : viewers_) {
-    viewer->OnArticleUpdated(article_update);
+  for (auto& viewer : viewers_) {
+    viewer.OnArticleUpdated(article_update);
   }
 }
 
diff --git a/chromium/components/dom_distiller/core/task_tracker.h b/chromium/components/dom_distiller/core/task_tracker.h
index 484145cf7d17..cc13e7272923 100644
--- a/chromium/components/dom_distiller/core/task_tracker.h
+++ b/chromium/components/dom_distiller/core/task_tracker.h
@@ -11,6 +11,7 @@
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
 #include "components/dom_distiller/core/article_distillation_update.h"
 #include "components/dom_distiller/core/article_entry.h"
 #include "components/dom_distiller/core/distiller.h"
@@ -40,9 +41,9 @@ class ViewerHandle {
 
 // Interface for a DOM distiller entry viewer. Implement this to make a view
 // request and receive the data for an entry when it becomes available.
-class ViewRequestDelegate {
+class ViewRequestDelegate : public base::CheckedObserver {
  public:
-  virtual ~ViewRequestDelegate() = default;
+  ~ViewRequestDelegate() override = default;
 
   // Called when the distilled article contents are available. The
   // DistilledArticleProto is owned by a TaskTracker instance and is invalidated
@@ -140,7 +141,7 @@ class TaskTracker {
   std::vector<SaveCallback> save_callbacks_;
   // A ViewRequestDelegate will be added to this list when a view request is
   // made and removed when the corresponding ViewerHandle is destroyed.
-  std::vector<ViewRequestDelegate*> viewers_;
+  base::ObserverList<ViewRequestDelegate> viewers_;
 
   std::unique_ptr<Distiller> distiller_;
   bool blob_fetcher_running_;