chore: remove unused Notification fields icon_path_, has_icon_ (#43286)

Last use of `icon_path_` was removed on May 29, 2017 (c741b584)
Last use of `has_icon_` was removed on May 30, 2017 (5048425e)

shell/browser/api/electron_api_notification.cc

@@ -58,10 +58,7 @@ Notification::Notification(gin::Arguments* args) {
     opts.Get("title", &title_);
     opts.Get("subtitle", &subtitle_);
     opts.Get("body", &body_);
-    has_icon_ = opts.Get("icon", &icon_);
-    if (has_icon_) {
-      opts.Get("icon", &icon_path_);
-    }
+    opts.Get("icon", &icon_);
     opts.Get("silent", &silent_);
     opts.Get("replyPlaceholder", &reply_placeholder_);
     opts.Get("urgency", &urgency_);

shell/browser/api/electron_api_notification.h

@@ -103,8 +103,6 @@ class Notification : public gin::Wrappable<Notification>,
   std::u16string subtitle_;
   std::u16string body_;
   gfx::Image icon_;
-  std::u16string icon_path_;
-  bool has_icon_ = false;
   bool silent_ = false;
   bool has_reply_ = false;
   std::u16string timeout_type_;