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..c23f44987d1d0097dfbfaae776d1df67f183159f
--- /dev/null
+++ b/chrome/browser/resources/settings/controls/controlled_button.html
@@ -0,0 +1,34 @@
+<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">
+  <link rel="import" type="css" href="chrome://resources/cr_elements/shared.css">
+  <template>
+    <style include="settings-shared">
+      :host {
+        align-items: center;
+        display: flex;
+      }
+
+      cr-policy-pref-indicator {
+        -webkit-margin-start: var(--checkbox-spacing);
+        pointer-events: all;
+      }
+    </style>
+
+    <paper-button disabled="[[disabled]]">
+      <content></content>
+    </paper-button>
+
+    <template is="dom-if" if="[[disabled]]">

[stevenjb, 2016/07/26 19:50:09]

If we use |disabled|, then I think this needs to be [[disabled && !!pref]]
(which will need to be wrapped in a function of course). <controlled-button
disabled> with no pref would be unexpected but valid.

[Dan Beam, 2016/07/26 22:28:40]

change to 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>