Bug 920927 - Fix plugin overlay handling. r=neil

browser/base/content/browser-plugins.js

@@ -313,7 +313,7 @@ var gPluginHandler = {
         break;
     }
 
-    // Hide the in-content UI if it's too big. The crashed plugin handler already did this.
+    // Show the in-content UI if it's not too big. The crashed plugin handler already did this.
     if (eventType != "PluginCrashed" && eventType != "PluginRemoved") {
       let overlay = this.getPluginUI(plugin, "main");
       if (overlay != null) {
@@ -989,12 +989,12 @@ var gPluginHandler = {
       if (this.isTooSmall(plugin, overlay)) {
         // Hide the overlay's contents. Use visibility style, so that it doesn't
         // collapse down to 0x0.
-        overlay.style.visibility = "hidden";
         isShowing = false;
       }
     }
 
     if (isShowing) {
+      overlay.style.visibility = "visible";
       // If a previous plugin on the page was too small and resulted in adding a
       // notification bar, then remove it because this plugin instance it big
       // enough to serve as in-content notification.

toolkit/mozapps/plugins/content/pluginProblemBinding.css

@@ -26,9 +26,6 @@ object:-moz-handler-playpreview,
 object:-moz-handler-vulnerable-updatable,
 object:-moz-handler-vulnerable-no-update {
     display: inline-block;
-    /* Initialize the overlay with visibility:hidden to prevent flickering if
-     * the plugin is too small to show the overlay */
-    visibility: hidden;
     overflow: hidden;
     opacity: 1 !important;
     -moz-binding: url('chrome://mozapps/content/plugins/pluginProblem.xml#pluginProblem') !important;

toolkit/mozapps/plugins/content/pluginProblemContent.css

@@ -42,6 +42,9 @@ html|applet:not([height]), html|applet[height=""] {
 .mainBox {
   width: inherit;
   height: inherit;
+  /* Initialize the overlay with visibility:hidden to prevent flickering if
+   * the plugin is too small to show the overlay */
+  visibility: hidden;
   overflow: hidden;
   direction: ltr;
   unicode-bidi: embed;