Remove unused feedback class in dom distiller component

chrome/browser/android/dom_distiller/distiller_ui_handle_android.h

Index: chrome/browser/android/dom_distiller/distiller_ui_handle_android.h
diff --git a/chrome/browser/android/dom_distiller/distiller_ui_handle_android.h b/chrome/browser/android/dom_distiller/distiller_ui_handle_android.h
index e64fc11d0e0fd5bb1aca9b4f788c5bdd1fde866c..e8a027cc0596a3d9fc4913ea5bc9ca2913c7a908 100644
--- a/chrome/browser/android/dom_distiller/distiller_ui_handle_android.h
+++ b/chrome/browser/android/dom_distiller/distiller_ui_handle_android.h
@@ -18,11 +18,6 @@ class DistillerUIHandleAndroid : public DistillerUIHandle {
   DistillerUIHandleAndroid() {}
   ~DistillerUIHandleAndroid() override {}
 
-  // ExternalFeedbackReporter implementation.
-  void ReportExternalFeedback(content::WebContents* web_contents,
-                              const GURL& url,
-                              const bool good) override;
-
   void OpenSettings(content::WebContents* web_contents) override;
 
   void ClosePanel(bool animate) override;