Remove all ReadingList entries on managed account signout.

components/reading_list/ios/favicon_web_state_dispatcher.h

Index: components/reading_list/ios/favicon_web_state_dispatcher.h
diff --git a/components/reading_list/ios/favicon_web_state_dispatcher.h b/components/reading_list/ios/favicon_web_state_dispatcher.h
index 4ffcbae2bfd2b63003cdd0415fce4101339a5566..a92217bd6ab1800e56d9c3c9fc1c2b802a8297ef 100644
--- a/components/reading_list/ios/favicon_web_state_dispatcher.h
+++ b/components/reading_list/ios/favicon_web_state_dispatcher.h
@@ -24,6 +24,9 @@ class FaviconWebStateDispatcher {
   // returned.
   virtual void ReturnWebState(std::unique_ptr<web::WebState> web_state) = 0;
 
+  // Releases all the WebState currently retained for favicon fetching.
+  virtual void ReleaseAll() = 0;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(FaviconWebStateDispatcher);
 };