Settings: Make Enable DRM checkbox available on all platforms

chrome/browser/resources/options/content_settings.html

 <div id="content-settings-page" class="page" hidden>
   <div class="close-button"></div>
   <h1 i18n-content="contentSettingsPage"></h1>
   <div class="content-area">
     <!-- Cookie filter tab contents -->
     <section>
       <h3 i18n-content="cookiesTabLabel"></h3>
       <div>
         <div class="radio controlled-setting-with-label">
           <label>
@@ skipping 286 matching lines @@
                   content-setting="notifications" value="block"></span>
             </span>
           </label>
         </div>
         <div class="settings-row">
           <button class="exceptions-list-button" contentType="notifications"
               i18n-content="manageExceptions"></button>
         </div>
       </div>
     </section>
-<if expr="chromeos or is_win">
     <!-- Protected Content filter -->
     <section guest-visibility="disabled">
       <h3 i18n-content="protectedContentTabLabel"
           class="content-settings-header"></h3>
       <div>
         <div class="settings-row">
           <p i18n-content="protectedContentInfo"></p>
         </div>
         <div class="checkbox">
           <label>
             <input pref="settings.privacy.drm_enabled" type="checkbox">
             <span i18n-content="protectedContentEnable"></span>
           </label>
         </div>
   <if expr="chromeos">
         <div class="settings-row">
           <button id="protected-content-exceptions"
               class="exceptions-list-button" contentType="protectedContent"
               i18n-content="manageExceptions"></button>
         </div>
   </if>
       </div>
     </section>
-</if>
     <!-- Microphone filter -->
     <section id="media-stream-mic">
       <h3 i18n-content="mediaStreamMicTabLabel"></h3>
       <div>
         <span id="media-select-mic-label"
             i18n-content="mediaSelectMicLabel" hidden></span>
         <select id="media-select-mic" class="weakrtl media-device-control"
             aria-labelledby="media-select-mic-label"></select>
         <div class="radio controlled-setting-with-label">
           <label>
@@ skipping 271 matching lines @@
     </section>
   </div>
   <div class="action-area">
     <div class="button-strip">
       <button id="content-settings-overlay-confirm" class="default-button"
           i18n-content="done">
       </button>
     </div>
   </div>
 </div>