diff --git a/content/browser/accessibility/browser_accessibility_manager.cc b/content/browser/accessibility/browser_accessibility_manager.cc
index 77d4c854..9975d7b 100644
--- a/content/browser/accessibility/browser_accessibility_manager.cc
+++ b/content/browser/accessibility/browser_accessibility_manager.cc
@@ -152,7 +152,9 @@
 BrowserAccessibilityManager::BrowserAccessibilityManager(
     BrowserAccessibilityDelegate* delegate,
     BrowserAccessibilityFactory* factory)
-    : delegate_(delegate),
+    : WebContentsObserver(delegate ? delegate->AccessibilityWebContents()
+                                   : nullptr),
+      delegate_(delegate),
       factory_(factory),
       tree_(new ui::AXSerializableTree()),
       user_is_navigating_away_(false),
@@ -168,7 +170,9 @@
     const ui::AXTreeUpdate& initial_tree,
     BrowserAccessibilityDelegate* delegate,
     BrowserAccessibilityFactory* factory)
-    : delegate_(delegate),
+    : WebContentsObserver(delegate ? delegate->AccessibilityWebContents()
+                                   : nullptr),
+      delegate_(delegate),
       factory_(factory),
       tree_(new ui::AXSerializableTree()),
       user_is_navigating_away_(false),
diff --git a/content/browser/accessibility/browser_accessibility_manager.h b/content/browser/accessibility/browser_accessibility_manager.h
index b5ff624..8ca497e8 100644
--- a/content/browser/accessibility/browser_accessibility_manager.h
+++ b/content/browser/accessibility/browser_accessibility_manager.h
@@ -19,6 +19,7 @@
 #include "content/browser/accessibility/browser_accessibility_position.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/ax_event_notification_details.h"
+#include "content/public/browser/web_contents_observer.h"
 #include "third_party/blink/public/web/web_ax_enums.h"
 #include "ui/accessibility/ax_action_data.h"
 #include "ui/accessibility/ax_event_generator.h"
@@ -88,6 +89,7 @@
   virtual gfx::NativeViewAccessible AccessibilityGetNativeViewAccessible() = 0;
   virtual gfx::NativeViewAccessible
   AccessibilityGetNativeViewAccessibleForWindow() = 0;
+  virtual WebContents* AccessibilityWebContents() = 0;
 
   // Returns true if this delegate represents the main (topmost) frame in a
   // tree of frames.
@@ -125,7 +127,8 @@
 
 // Manages a tree of BrowserAccessibility objects.
 class CONTENT_EXPORT BrowserAccessibilityManager : public ui::AXTreeObserver,
-                                                   public ui::AXTreeManager {
+                                                   public ui::AXTreeManager,
+                                                   public WebContentsObserver {
  protected:
   using BrowserAccessibilityPositionInstance =
       BrowserAccessibilityPosition::AXPositionInstance;
@@ -188,11 +191,14 @@
   virtual void OnWindowBlurred();
 
   // Notify the accessibility manager about page navigation.
+  // TODO(domfarolino, dmazzoni): Implement WebContentsObserver methods that
+  // correspond to the ones we provide today, so we can stop being manually
+  // notified of navigation events when they happen.
   void UserIsNavigatingAway();
   virtual void UserIsReloading();
   void NavigationSucceeded();
   void NavigationFailed();
-  void DidStopLoading();
+  void DidStopLoading() override;
 
   // Keep track of if this page is hidden by an interstitial, in which case
   // we need to suppress all events.
diff --git a/content/browser/accessibility/test_browser_accessibility_delegate.cc b/content/browser/accessibility/test_browser_accessibility_delegate.cc
index eabb8180..4679bc6 100644
--- a/content/browser/accessibility/test_browser_accessibility_delegate.cc
+++ b/content/browser/accessibility/test_browser_accessibility_delegate.cc
@@ -46,6 +46,10 @@
   return nullptr;
 }
 
+WebContents* TestBrowserAccessibilityDelegate::AccessibilityWebContents() {
+  return nullptr;
+}
+
 bool TestBrowserAccessibilityDelegate::AccessibilityIsMainFrame() const {
   return is_root_frame_;
 }
diff --git a/content/browser/accessibility/test_browser_accessibility_delegate.h b/content/browser/accessibility/test_browser_accessibility_delegate.h
index 10dca8b..d42f436 100644
--- a/content/browser/accessibility/test_browser_accessibility_delegate.h
+++ b/content/browser/accessibility/test_browser_accessibility_delegate.h
@@ -22,6 +22,7 @@
   gfx::NativeViewAccessible AccessibilityGetNativeViewAccessible() override;
   gfx::NativeViewAccessible AccessibilityGetNativeViewAccessibleForWindow()
       override;
+  WebContents* AccessibilityWebContents() override;
   bool AccessibilityIsMainFrame() const override;
 
   bool got_fatal_error() const;
diff --git a/content/browser/frame_host/frame_tree_node.cc b/content/browser/frame_host/frame_tree_node.cc
index d38d9d0..f367008b 100644
--- a/content/browser/frame_host/frame_tree_node.cc
+++ b/content/browser/frame_host/frame_tree_node.cc
@@ -516,6 +516,8 @@
 
   // Notify accessibility that the user is no longer trying to load or
   // reload a page.
+  // TODO(domfarolino): Remove this in favor of notifying via the delegate's
+  // DidStopLoading() above.
   BrowserAccessibilityManager* manager =
       current_frame_host()->browser_accessibility_manager();
   if (manager)
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 8da26c2..7437f47 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -1636,6 +1636,10 @@
   return nullptr;
 }
 
+WebContents* RenderFrameHostImpl::AccessibilityWebContents() {
+  return delegate()->GetAsWebContents();
+}
+
 bool RenderFrameHostImpl::AccessibilityIsMainFrame() const {
   return frame_tree_node()->IsMainFrame();
 }
diff --git a/content/browser/frame_host/render_frame_host_impl.h b/content/browser/frame_host/render_frame_host_impl.h
index 18ab36f8..72aea75c 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -309,6 +309,7 @@
   gfx::NativeViewAccessible AccessibilityGetNativeViewAccessible() override;
   gfx::NativeViewAccessible AccessibilityGetNativeViewAccessibleForWindow()
       override;
+  WebContents* AccessibilityWebContents() override;
   bool AccessibilityIsMainFrame() const override;
 
   // RenderProcessHostObserver implementation.
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index 6053638..a798653 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -1851,8 +1851,9 @@
 }
 
 BrowserAccessibilityManager*
-    RenderWidgetHostViewAndroid::CreateBrowserAccessibilityManager(
-        BrowserAccessibilityDelegate* delegate, bool for_root_frame) {
+RenderWidgetHostViewAndroid::CreateBrowserAccessibilityManager(
+    BrowserAccessibilityDelegate* delegate,
+    bool for_root_frame) {
   return new BrowserAccessibilityManagerAndroid(
       BrowserAccessibilityManagerAndroid::GetEmptyDocument(),
       for_root_frame && host() ? GetWebContentsAccessibilityAndroid() : nullptr,
diff --git a/content/browser/renderer_host/render_widget_host_view_android.h b/content/browser/renderer_host/render_widget_host_view_android.h
index 7089548..6c689f62 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.h
+++ b/content/browser/renderer_host/render_widget_host_view_android.h
@@ -149,7 +149,8 @@
                                     bool down) override;
   void FallbackCursorModeSetCursorVisibility(bool visible) override;
   BrowserAccessibilityManager* CreateBrowserAccessibilityManager(
-      BrowserAccessibilityDelegate* delegate, bool for_root_frame) override;
+      BrowserAccessibilityDelegate* delegate,
+      bool for_root_frame) override;
   bool LockMouse() override;
   void UnlockMouse() override;
   void DidCreateNewRendererCompositorFrameSink(
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index 1befcdd..aec7d21 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -1122,7 +1122,8 @@
 
 BrowserAccessibilityManager*
 RenderWidgetHostViewAura::CreateBrowserAccessibilityManager(
-    BrowserAccessibilityDelegate* delegate, bool for_root_frame) {
+    BrowserAccessibilityDelegate* delegate,
+    bool for_root_frame) {
   BrowserAccessibilityManager* manager = nullptr;
 #if defined(OS_WIN)
   manager = new BrowserAccessibilityManagerWin(
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.h b/content/browser/renderer_host/render_widget_host_view_aura.h
index 50b2161..86a98b25 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.h
+++ b/content/browser/renderer_host/render_widget_host_view_aura.h
@@ -155,7 +155,8 @@
   InputEventAckState FilterChildGestureEvent(
       const blink::WebGestureEvent& gesture_event) override;
   BrowserAccessibilityManager* CreateBrowserAccessibilityManager(
-      BrowserAccessibilityDelegate* delegate, bool for_root_frame) override;
+      BrowserAccessibilityDelegate* delegate,
+      bool for_root_frame) override;
   gfx::AcceleratedWidget AccessibilityGetAcceleratedWidget() override;
   gfx::NativeViewAccessible AccessibilityGetNativeViewAccessible() override;
   void SetMainFrameAXTreeID(ui::AXTreeID id) override;
diff --git a/content/browser/renderer_host/render_widget_host_view_base.cc b/content/browser/renderer_host/render_widget_host_view_base.cc
index 5a3b90ec..f960f6c 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.cc
+++ b/content/browser/renderer_host/render_widget_host_view_base.cc
@@ -459,7 +459,8 @@
 
 BrowserAccessibilityManager*
 RenderWidgetHostViewBase::CreateBrowserAccessibilityManager(
-    BrowserAccessibilityDelegate* delegate, bool for_root_frame) {
+    BrowserAccessibilityDelegate* delegate,
+    bool for_root_frame) {
   NOTREACHED();
   return nullptr;
 }
diff --git a/content/browser/renderer_host/render_widget_host_view_base.h b/content/browser/renderer_host/render_widget_host_view_base.h
index a5f11d9..11cd489 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.h
+++ b/content/browser/renderer_host/render_widget_host_view_base.h
@@ -270,7 +270,8 @@
   // suitable for the root frame, which may be linked to its native
   // window container.
   virtual BrowserAccessibilityManager* CreateBrowserAccessibilityManager(
-      BrowserAccessibilityDelegate* delegate, bool for_root_frame);
+      BrowserAccessibilityDelegate* delegate,
+      bool for_root_frame);
 
   virtual void AccessibilityShowMenu(const gfx::Point& point);
   virtual gfx::AcceleratedWidget AccessibilityGetAcceleratedWidget();
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.h b/content/browser/renderer_host/render_widget_host_view_mac.h
index 21a19bd..0eeacea 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.h
+++ b/content/browser/renderer_host/render_widget_host_view_mac.h
@@ -159,7 +159,8 @@
   void ResetFallbackToFirstNavigationSurface() override;
   bool RequestRepaintForTesting() override;
   BrowserAccessibilityManager* CreateBrowserAccessibilityManager(
-      BrowserAccessibilityDelegate* delegate, bool for_root_frame) override;
+      BrowserAccessibilityDelegate* delegate,
+      bool for_root_frame) override;
   gfx::NativeViewAccessible AccessibilityGetNativeViewAccessible() override;
   gfx::NativeViewAccessible AccessibilityGetNativeViewAccessibleForWindow()
       override;
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index 6845707..ac6ce63 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -1382,8 +1382,9 @@
 }
 
 BrowserAccessibilityManager*
-    RenderWidgetHostViewMac::CreateBrowserAccessibilityManager(
-        BrowserAccessibilityDelegate* delegate, bool for_root_frame) {
+RenderWidgetHostViewMac::CreateBrowserAccessibilityManager(
+    BrowserAccessibilityDelegate* delegate,
+    bool for_root_frame) {
   return new BrowserAccessibilityManagerMac(
       BrowserAccessibilityManagerMac::GetEmptyDocument(), delegate);
 }
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 0a3d626..37e9397c 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -4327,6 +4327,8 @@
     display_cutout_host_impl_->DidFinishNavigation(navigation_handle);
 
   if (navigation_handle->HasCommitted()) {
+    // TODO(domfarolino, dmazzoni): Do this using WebContentsObserver. See
+    // https://crbug.com/981271.
     BrowserAccessibilityManager* manager =
         static_cast<RenderFrameHostImpl*>(
             navigation_handle->GetRenderFrameHost())
@@ -5819,8 +5821,8 @@
 
   // Notify accessibility that the user is navigating away from the
   // current document.
-  //
-  // TODO(dmazzoni): do this using a WebContentsObserver.
+  // TODO(domfarolino, dmazzoni): Do this using WebContentsObserver. See
+  // https://crbug.com/981271.
   BrowserAccessibilityManager* manager =
       frame_tree_node->current_frame_host()->browser_accessibility_manager();
   if (manager)