Site Settings: Implement dialog for adding site exceptions.

chrome/browser/resources/settings/site_settings/site_settings_prefs_browser_proxy.js

Index: chrome/browser/resources/settings/site_settings/site_settings_prefs_browser_proxy.js
diff --git a/chrome/browser/resources/settings/site_settings/site_settings_prefs_browser_proxy.js b/chrome/browser/resources/settings/site_settings/site_settings_prefs_browser_proxy.js
index 45f6bc6a7023e8e91ba73a5795f18a182a51971c..e70d087a3a670e2979d3c085a709350e0349762b 100644
--- a/chrome/browser/resources/settings/site_settings/site_settings_prefs_browser_proxy.js
+++ b/chrome/browser/resources/settings/site_settings/site_settings_prefs_browser_proxy.js
@@ -82,6 +82,13 @@ cr.define('settings', function() {
      */
     setCategoryPermissionForOrigin: function(
         primaryPattern, secondaryPattern, contentType, value) {},
+
+    /**
+     * Checks whether a pattern is valid.
+     * @param {string} pattern The pattern to check
+     * @return {!Promise<boolean>} True if the pattern is valid.
+     */
+    isPatternValid: function(pattern) {},
   };
 
   /**
@@ -123,6 +130,12 @@ cr.define('settings', function() {
       chrome.send('setCategoryPermissionForOrigin',
           [primaryPattern, secondaryPattern, contentType, value]);
     },
+
+    /** @override */
+    isPatternValid: function(pattern) {
+      return cr.sendWithPromise('isPatternValid', pattern);
+    },
+
   };
 
   return {