Add managed user lock/unlock button for the extensions page.

chrome/browser/resources/extensions/extensions.html

Index: chrome/browser/resources/extensions/extensions.html
diff --git a/chrome/browser/resources/extensions/extensions.html b/chrome/browser/resources/extensions/extensions.html
index a2f8704a24b8144c85b83d88e442008c8c5cfefc..834e50da744ddf63bb5ac9a807758357c13581bd 100644
--- a/chrome/browser/resources/extensions/extensions.html
+++ b/chrome/browser/resources/extensions/extensions.html
@@ -38,10 +38,18 @@
 
 <div class="page" id="extension-settings">
   <header id="page-header"><h1 i18n-content="extensionSettings"></h1>
-    <div id="dev-toggle" class="checkbox header-extras"><label>
-      <input id="toggle-dev-on" type="checkbox">
-      <span i18n-content="extensionSettingsDeveloperMode">
-    </label></div>
+    <div id="header-controls" class="header-extras">
+      <div id="dev-toggle" class="checkbox">
+        <label>
+          <input id="toggle-dev-on" type="checkbox">
+          <span i18n-content="extensionSettingsDeveloperMode">
+        </label>
+      </div>
+      <div id="managed-user-control-div">
+        <button id="unlock-button" i18n-content="unlockButton"></button>
+        <button id="lock-button" i18n-content="lockButton"></button>
+      </div>
+    </div>
     <div class="page-banner profile-is-managed-banner">
       <div class="page-banner-gradient">
         <span class="page-banner-text"