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 32a11dd9be3a867304de28a005030d553062d000..2d2f36a7511a24bb14b0d2ef08397402a01d2daa 100644
--- a/content/public/browser/web_contents_observer.h
+++ b/content/public/browser/web_contents_observer.h
@@ -446,12 +446,11 @@ 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
+  // AccessibilityModeFlagWebContents 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) {}