MD Settings: Content Settings: Support guest mode.

chrome/browser/resources/settings/privacy_page/privacy_page.html

Index: chrome/browser/resources/settings/privacy_page/privacy_page.html
diff --git a/chrome/browser/resources/settings/privacy_page/privacy_page.html b/chrome/browser/resources/settings/privacy_page/privacy_page.html
index f1d1a282442aaa696f5502301b5408e895102fc2..cbb7fc7bce95da14d417eb43685fb445cf2f677a 100644
--- a/chrome/browser/resources/settings/privacy_page/privacy_page.html
+++ b/chrome/browser/resources/settings/privacy_page/privacy_page.html
@@ -423,7 +423,8 @@
             <settings-toggle-button class="start"
                 pref="{{prefs.webkit.webprefs.encrypted_media_enabled}}"
                 label="[[getProtectedContentLabel_(
-                    prefs.webkit.webprefs.encrypted_media_enabled.value)]]">
+                    prefs.webkit.webprefs.encrypted_media_enabled.value)]]"
+                disabled$="[[isGuest_]]">

[tommycli, 2017/02/14 00:28:39]

The existing usages of isGuest_ in the code specify that the control is entirely
gone (dom-ifed out). In these cases UI specified it should be just disabled?

[stevenjb, 2017/02/14 00:49:23]

This is consistent with current Settings. I stuck with this model because:
a) Exceptions can still be added
b) It may help explain to the user why it doesn't work. Ideally at some point we
could add a policy like icon here with an explanatory tooltip.

             </settings-toggle-button>
           </div>
 <if expr="chromeos or is_win">
@@ -434,7 +435,8 @@
             <settings-toggle-button class="start"
                 pref="{{prefs.settings.privacy.drm_enabled}}"
                 label="[[getProtectedContentIdentifiersLabel_(
-                    prefs.settings.privacy.drm_enabled.value)]]">
+                    prefs.settings.privacy.drm_enabled.value)]]"
+                disabled$="[[isGuest_]]">
             </settings-toggle-button>
           </div>
 </if>