md-settings: wrap lock screen dialogs in dom-if.

chrome/browser/resources/settings/people_page/lock_screen.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 
 <link rel="import" href="chrome://resources/html/assert.html">
 <link rel="import" href="chrome://resources/html/cr/ui/focus_without_ink.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-radio-group/paper-radio-group.html">
 <link rel="import" href="../controls/settings_toggle_button.html">
 <link rel="import" href="easy_unlock_browser_proxy.html">
@@ skipping 142 matching lines @@
           </template>
           <template is="dom-if" if="[[easyUnlockEnabled_]]">
             <paper-button id="easyUnlockTurnOff" class="secondary-button"
                 on-tap="onEasyUnlockTurnOffTap_">
               $i18n{easyUnlockTurnOffButton}
             </paper-button>
           </template>
         </div>
       </template>
 
-      <settings-password-prompt-dialog id="passwordPrompt"
-          on-close="onPasswordClosed_" set-modes="{{setModes_}}">
-      </settings-password-prompt-dialog>
+      <template is="dom-if" if="[[showPasswordPromptDialog_]]" restamp>
+        <settings-password-prompt-dialog id="passwordPrompt"
+            on-close="onPasswordPromptDialogClose_" set-modes="{{setModes_}}">
+        </settings-password-prompt-dialog>
+      </template>
 
-      <settings-setup-pin-dialog id="setupPin" on-done="onPinSetupDone_"
-          on-close="onSetupPinClosed_" set-modes="[[setModes_]]">
-      </settings-setup-pin-dialog>
+      <template is="dom-if" if="[[showSetupPinDialog_]]" restamp>
+        <settings-setup-pin-dialog id="setupPin" set-modes="[[setModes_]]"
+            on-close="onSetupPinDialogClose_">
+        </settings-setup-pin-dialog>
+      </template>
 
       <template is="dom-if" if="[[showEasyUnlockTurnOffDialog_]]" restamp>
         <easy-unlock-turn-off-dialog id="easyUnlockTurnOffDialog"
             on-close="onEasyUnlockTurnOffDialogClose_">
         </easy-unlock-turn-off-dialog>
       </template>
     </div>
   </template>
 
   <script src="lock_screen.js"></script>
 </dom-module>