MD Settings: Remove usage of deprecated iron-flex-layout.html, for CrOS.

chrome/browser/resources/settings/internet_page/network_proxy.html

 <link rel="import" href="chrome://resources/cr_elements/cr_dialog/cr_dialog.html">
+<link rel="import" href="chrome://resources/cr_elements/hidden_style_css.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_onc_types.html">
 <link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_network_behavior.html">
 <link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_network_indicator.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
 <link rel="import" href="chrome://resources/html/md_select_css.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-a11y-keys/iron-a11y-keys.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-input/paper-input-container.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-input/paper-input.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-toggle-button/paper-toggle-button.html">
 <link rel="import" href="../controls/extension_controlled_indicator.html">
 <link rel="import" href="../controls/settings_toggle_button.html">
 <link rel="import" href="../i18n_setup.html">
 <link rel="import" href="../prefs/prefs_behavior.html">
 <link rel="import" href="../settings_vars_css.html">
 <link rel="import" href="internet_shared_css.html">
 <link rel="import" href="network_proxy_exclusions.html">
 <link rel="import" href="network_proxy_input.html">
 
 <dom-module id="network-proxy">
   <template>
-    <style include="internet-shared md-select">
+    <style include="internet-shared md-select cr-hidden-style">
       cr-policy-network-indicator {
         -webkit-margin-end: 10px;
       }
 
       extension-controlled-indicator {
         -webkit-margin-start: 0;
         width: 100%;
       }
 
       network-proxy-input {
@@ skipping 176 matching lines @@
         </paper-button>
         <paper-button class="action-button"
             on-tap="onAllowSharedDialogConfirm_">
           $i18n{confirm}
         </paper-button>
       </div>
     </dialog>
   </template>
   <script src="network_proxy.js"></script>
 </dom-module>