Add an extension override bubble and warning box for proxy extensions.

chrome/browser/resources/options/browser_options.js

Index: chrome/browser/resources/options/browser_options.js
diff --git a/chrome/browser/resources/options/browser_options.js b/chrome/browser/resources/options/browser_options.js
index 59fe9ebd4ae955efac37bb08999569084ed71ec5..c5fd816d04aa3b2ab4c2fbad9fefd0501d113a92 100644
--- a/chrome/browser/resources/options/browser_options.js
+++ b/chrome/browser/resources/options/browser_options.js
@@ -573,6 +573,9 @@ cr.define('options', function() {
       this.addExtensionControlledBox_('newtab-section-content',
                                       'newtab-controlled',
                                       false);
+      this.addExtensionControlledBox_('proxy-section-content',
+                                      'proxy-controlled',
+                                      true);
 
       document.body.addEventListener('click', function(e) {
         var button = findAncestor(e.target, function(el) {
@@ -1508,10 +1511,14 @@ cr.define('options', function() {
     },
 
     /**
-     * Set the enabled state for the proxy settings button.
+     * Set the enabled state for the proxy settings button and its associated
+     * message when extension controlled.
+     * @param {boolean} disabled Whether the button should be disabled.
+     * @param {boolean} extensionControlled Whether the proxy is extension
+     *     controlled.
      * @private
      */
-    setupProxySettingsSection_: function(disabled, extensionControlled) {
+    setupProxySettingsButton_: function(disabled, extensionControlled) {
       if (!cr.isChromeOS) {
         $('proxiesConfigureButton').disabled = disabled;
         $('proxiesLabel').textContent =
@@ -1626,6 +1633,15 @@ cr.define('options', function() {
                                          'newtab-controlled',
                                          details.newTabPage.id,
                                          details.newTabPage.name);
+      this.toggleExtensionControlledBox_('proxy-section-content',
+                                         'proxy-controlled',
+                                         details.proxy.id,
+                                         details.proxy.name);
+
+      // The proxy section contains just the warning box and nothing else, so
+      // if we're hiding the proxy warning box, we should also hide its header
+      // section.
+      $('proxy-section').hidden = details.proxy.id.length == 0;
     },
 
 
@@ -1794,7 +1810,7 @@ cr.define('options', function() {
     'setThemesResetButtonEnabled',
     'setVirtualKeyboardCheckboxState',
     'setupPageZoomSelector',
-    'setupProxySettingsSection',
+    'setupProxySettingsButton',
     'showBluetoothSettings',
     'showCreateProfileError',
     'showCreateProfileSuccess',