Chromium change: https://chromium.googlesource.com/chromium/src/+/dfdd24a54d2dc4d911e01f58571a34f4dd277ef5 [Toolbar] Move ButtonData classes from chrome.browser.toolbar to chrome.browser.toolbar.optional_button package. Planning to create new "ToolbarButton*" classes to manage common code for different toolbar buttons and want to avoid naming confusion with optional button code Bug: 409638002