Add more fine-grained accessibility modes.

content/public/browser/web_contents_observer.h

Index: content/public/browser/web_contents_observer.h
diff --git a/content/public/browser/web_contents_observer.h b/content/public/browser/web_contents_observer.h
index 6d945a20676b389f226a9e87771053abfd2c5f30..74218f22e802ac54244c7f3ca99d489e54964093 100644
--- a/content/public/browser/web_contents_observer.h
+++ b/content/public/browser/web_contents_observer.h
@@ -445,12 +445,11 @@ class CONTENT_EXPORT WebContentsObserver : public IPC::Listener,
   // Invoked when a user cancels a before unload dialog.
   virtual void BeforeUnloadDialogCancelled() {}
 
-  // Invoked when an accessibility event is received from the renderer process.
+  // Called when accessibility events or location changes are received
+  // from a render frame, but only when the accessibility mode has the
+  // ACCESSIBILITY_MODE_FLAG_WEB_CONTENTS flag set.
   virtual void AccessibilityEventReceived(
       const std::vector<AXEventNotificationDetails>& details) {}
-
-  // Invoked when an accessibility location change is received from the
-  // renderer process.
   virtual void AccessibilityLocationChangesReceived(
       const std::vector<AXLocationChangeNotificationDetails>& details) {}