MD Settings: add a <controlled-button> that uses prefs to disable itself

chrome/browser/resources/settings/controls/controlled_button.html

Index: chrome/browser/resources/settings/controls/controlled_button.html
diff --git a/chrome/browser/resources/settings/controls/controlled_button.html b/chrome/browser/resources/settings/controls/controlled_button.html
new file mode 100644
index 0000000000000000000000000000000000000000..5c028340f6a2a0deaa4e45a16cf9f107622548cd
--- /dev/null
+++ b/chrome/browser/resources/settings/controls/controlled_button.html
@@ -0,0 +1,41 @@
+<link rel="import" href="chrome://resources/html/polymer.html">
+<link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
+<link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_pref_behavior.html">
+<link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_pref_indicator.html">
+<link rel="import" href="/controls/pref_control_behavior.html">
+<link rel="import" href="/settings_shared_css.html">
+
+<dom-module id="controlled-button">
+  <template>
+    <style include="settings-shared">
+      :host {
+        align-items: center;
+        display: flex;
+      }
+
+      :host([controlled_]) {
+        /* Disable pointer events for this whole element, as outer on-tap gets
+         * triggered when clicking/tapping anywhere in :host. */
+        pointer-events: none;
+      }
+
+      cr-policy-pref-indicator {
+        -webkit-margin-start: var(--checkbox-spacing);
+        /* Enable pointer events for the indicator so :hover works. Disable
+         * clicks/taps via onIndicatorTap_ so outer on-tap doesn't trigger. */
+        pointer-events: all;
+      }
+    </style>
+
+    <paper-button disabled="[[controlled_]]">
+      <content></content>
+    </paper-button>
+
+    <template is="dom-if" if="[[controlled_]]">
+      <cr-policy-pref-indicator pref="[[pref]]" on-tap="onIndicatorTap_">
+      </cr-policy-pref-indicator>
+    </template>
+
+  </template>
+  <script src="/controls/controlled_button.js"></script>
+</dom-module>