MD Settings: don't allow supervised users to switch to GTK+ theme

chrome/browser/resources/settings/appearance_page/appearance_page.html

Index: chrome/browser/resources/settings/appearance_page/appearance_page.html
diff --git a/chrome/browser/resources/settings/appearance_page/appearance_page.html b/chrome/browser/resources/settings/appearance_page/appearance_page.html
index 6237a7644459f28dc872568d0c9ecf0648dfcd36..67da00c292bf4a16623a52d4b52705863ee9a0b8 100644
--- a/chrome/browser/resources/settings/appearance_page/appearance_page.html
+++ b/chrome/browser/resources/settings/appearance_page/appearance_page.html
@@ -67,22 +67,25 @@
           </template>
 </if>
 <if expr="is_linux and not chromeos">
-          <div class="secondary-action">
-            <template is="dom-if" if="[[showUseClassic_(
-                prefs.extensions.theme.id.value, useSystemTheme_)]]" restamp>
-              <paper-button id="useDefault" on-tap="onUseDefaultTap_"
-                  class="secondary-button">
-                $i18n{useClassicTheme}
-              </paper-button>
-            </template>
-            <template is="dom-if" if="[[showUseSystem_(
-                prefs.extensions.theme.id.value, useSystemTheme_)]]" restamp>
-              <paper-button id="useSystem" on-tap="onUseSystemTap_"
-                  class="secondary-button">
-                $i18n{useSystemTheme}
-              </paper-button>
-            </template>
-          </div>
+          <template is="dom-if" if="[[showThemesSecondary_(
+              prefs.extensions.theme.id.value, useSystemTheme_)]]">
+            <div class="secondary-action">

[dpapad, 2016/10/18 17:49:34]

Can we just make this div hidden instead of wrapping the entire div with a new
dom-if? Performance wise, this will be an empty <div> when hidden, so not a big
deal.

[Dan Beam, 2016/10/18 18:59:52]

Done.

+              <template is="dom-if" if="[[showUseClassic_(
+                  prefs.extensions.theme.id.value, useSystemTheme_)]]" restamp>
+                <paper-button id="useDefault" on-tap="onUseDefaultTap_"
+                    class="secondary-button">
+                  $i18n{useClassicTheme}
+                </paper-button>
+              </template>
+              <template is="dom-if" if="[[showUseSystem_(

[dpapad, 2016/10/18 17:49:34]

Can we add a test regarding showing/hiding the theme buttons based on policy (or
anything else that shows/hides those buttons)?

[Dan Beam, 2016/10/18 18:59:52]

Done.

+                  prefs.extensions.theme.id.value, useSystemTheme_)]]" restamp>
+                <paper-button id="useSystem" on-tap="onUseSystemTap_"
+                    class="secondary-button">
+                  $i18n{useSystemTheme}
+                </paper-button>
+              </template>
+            </div>
+          </template>
 </if>
         </div>
         <div class="settings-box"