Add setting to isolate zoom changes by default.

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview A helper object used from the "Site Settings" section to
  * interact with the content settings prefs.
  */
 
 /**
@@ skipping 252 matching lines @@
      */
     removeUsbDevice: function(origin, embeddingOrigin, usbDevice) {},
 
     /**
      * Fetches the incognito status of the current profile (whether an icognito
      * profile exists). Returns the results via onIncognitoStatusChanged.
      */
     updateIncognitoStatus: function() {},
 
     /**
+     * Fetches the zoom scope setting. Returns the result via
+     * onZoomScopeChanged.
+     */
+    fetchZoomScope: function() {},
+
+    /**
      * Fetches the currently defined zoom levels for sites. Returns the results
      * via onZoomLevelsChanged.
      */
     fetchZoomLevels: function() {},
 
     /**
+     * Sets whether the zoom scope is per-origin or per-tab.
+     * @param {boolean} zoomScopeIsPerOrigin The zoom scope setting.
+     */
+    setZoomScopeIsPerOrigin: function(zoomScopeIsPerOrigin) {},
+
+    /**
      * Removes a zoom levels for a given host.
      * @param {string} host The host to remove zoom levels for.
      */
     removeZoomLevel: function(host) {},
   };
 
   /**
    * @constructor
    * @implements {settings.SiteSettingsPrefsBrowserProxy}
    */
@@ skipping 112 matching lines @@
     removeUsbDevice: function(origin, embeddingOrigin, usbDevice) {
       chrome.send('removeUsbDevice', [origin, embeddingOrigin, usbDevice]);
     },
 
     /** @override */
     updateIncognitoStatus: function() {
       chrome.send('updateIncognitoStatus');
     },
 
     /** @override */
+    fetchZoomScope: function() {
+      chrome.send('fetchZoomScope');
+    },
+
+    /** @override */
     fetchZoomLevels: function() {
       chrome.send('fetchZoomLevels');
     },
 
     /** @override */
+    setZoomScopeIsPerOrigin: function(zoomScopeIsPerOrigin) {
+      chrome.send('setZoomScopeIsPerOrigin', [zoomScopeIsPerOrigin]);
+    },
+
+    /** @override */
     removeZoomLevel: function(host) {
       chrome.send('removeZoomLevel', [host]);
     },
   };
 
   return {
     SiteSettingsPrefsBrowserProxy: SiteSettingsPrefsBrowserProxy,
     SiteSettingsPrefsBrowserProxyImpl: SiteSettingsPrefsBrowserProxyImpl,
   };
 });