MDL-77646 lib: Use iframe instead of object to display pdf.

lib/resourcelib.php

@@ -233,13 +233,12 @@ function resourcelib_embed_pdf($fullurl, $title, $clicktoopen) {
     global $CFG, $PAGE;
 
     $code = <<<EOT
-<div class="resourcecontent resourcepdf">
-  <object id="resourceobject" data="$fullurl" type="application/pdf" width="800" height="600">
-    <param name="src" value="$fullurl" />
-    $clicktoopen
-  </object>
-</div>
-EOT;
+    <div class="resourcecontent resourcepdf">
+         <iframe id="resourceobject" src="$fullurl" title="$title" width="800" height="600">
+             $clicktoopen
+         </iframe>
+    </div>
+    EOT;
 
     // the size is hardcoded in the boject obove intentionally because it is adjusted by the following function on-the-fly
     $PAGE->requires->js_init_call('M.util.init_maximised_embed', array('resourceobject'), true);