MD Settings: Adding C++ support for editing startup URLs.

chrome/browser/resources/settings/on_startup_page/startup_urls_page_browser_proxy.js

Index: chrome/browser/resources/settings/on_startup_page/startup_urls_page_browser_proxy.js
diff --git a/chrome/browser/resources/settings/on_startup_page/startup_urls_page_browser_proxy.js b/chrome/browser/resources/settings/on_startup_page/startup_urls_page_browser_proxy.js
index d286a2f59235d7411a9d9a00454f6fed7a2e3a11..3594a305a3966cc7df7db630a0fd5ea5cb82f6b1 100644
--- a/chrome/browser/resources/settings/on_startup_page/startup_urls_page_browser_proxy.js
+++ b/chrome/browser/resources/settings/on_startup_page/startup_urls_page_browser_proxy.js
@@ -24,6 +24,14 @@ cr.define('settings', function() {
      */
     addStartupPage: assertNotReached,
 
+    /**
+     * @param {number} modelIndex
+     * @param {string} url
+     * @return {!Promise<boolean>} Whether the URL was actually edited, or
+     *     ignored because it was invalid.
+     */
+    editStartupPage: assertNotReached,
+
     /** @param {number} index */
     removeStartupPage: assertNotReached,
   };
@@ -58,6 +66,11 @@ cr.define('settings', function() {
     },
 
     /** @override */
+    editStartupPage: function(modelIndex, url) {
+      return cr.sendWithPromise('editStartupPage', modelIndex, url);
+    },
+
+    /** @override */
     removeStartupPage: function(index) {
       chrome.send('removeStartupPage', [index]);
     },