MDL-55462 output: Make help_icon templatable

Render it with a template in the new theme.

Part of MDL-55071

lib/outputcomponents.php

@@ -447,7 +447,7 @@ public function get_url(moodle_page $page, renderer_base $renderer = null) {
  * @package core
  * @category output
  */
-class help_icon implements renderable {
+class help_icon implements renderable, templatable {
 
     /**
      * @var string lang pack identifier (without the "_help" suffix),
@@ -491,6 +491,28 @@ public function diag_strings() {
             debugging("Help contents string does not exist: [{$this->identifier}_help, $this->component]");
         }
     }
+
+    /**
+     * Export this data so it can be used as the context for a mustache template.
+     *
+     * @param renderer_base $output Used to do a final render of any components that need to be rendered for export.
+     * @return array
+     */
+    public function export_for_template(renderer_base $output) {
+        $title = get_string($this->identifier, $this->component);
+
+        if (empty($this->linktext)) {
+            $alt = get_string('helpprefix2', '', trim($title, ". \t"));
+        } else {
+            $alt = get_string('helpwiththis');
+        }
+
+        $data = get_formatted_help_string($this->identifier, $this->component, false);
+        $data->alt = $alt;
+
+        $data->ltr = !right_to_left();
+        return $data;
+    }
 }
 
 

theme/noname/classes/output/core_renderer.php

@@ -27,6 +27,7 @@
 use moodle_url;
 use preferences_groups;
 use action_menu;
+use help_icon;
 
 defined('MOODLE_INTERNAL') || die;
 
@@ -261,4 +262,14 @@ public function render_action_menu(action_menu $menu) {
         return $this->render_from_template('core/action_menu', $menu);
     }
 
+    /**
+     * Implementation of user image rendering.
+     *
+     * @param help_icon $helpicon A help icon instance
+     * @return string HTML fragment
+     */
+    protected function render_help_icon(help_icon $helpicon) {
+        $context = $helpicon->export_for_template($this);
+        return $this->render_from_template('core/help_icon', $context);
+    }
 }

theme/noname/templates/core/help_icon.mustache

@@ -0,0 +1,6 @@
+<button class="btn btn-link p-a-0"
+    data-container="body" data-toggle="popover"
+    data-placement="{{#ltr}}right{{/ltr}}{{^ltr}}left{{/ltr}}" data-content="{{text}} {{completedoclink}}"
+    data-html="true" tabindex="0" data-trigger="click">
+  {{#pix}}help, core, {{alt}}{{/pix}}
+</button>