ruffle: fix issue with ruffle falsely triggering keyboard shortcuts.

Fix issue mentioned in 55980c6fb with Javascript spazzing out on Flash
posts and randomly triggering keyboard shortcuts.

The bug was calling `javascript_pack_tag` twice. This caused the
runtime Javascript chunk to be loaded twice, caused a lot of Javascript
errors that somehow resulted in keyboard shortcuts being triggered.

The fix is to combine both calls into `javascript_pack_tag "application", "flash"`.

hxxps://github.com.rails.webpacker.issues.2932

app/javascript/src/javascripts/posts.js.erb

@@ -35,6 +35,7 @@ Post.initialize_all = function() {
     this.initialize_post_image_resize_links();
     this.initialize_recommended();
     this.initialize_ugoira_player();
+    this.initialize_ruffle_player();
   }
 
   if ($("#c-posts #a-show, #c-uploads #a-new").length) {
@@ -380,6 +381,19 @@ Post.initialize_ugoira_player = function() {
   }
 };
 
+Post.initialize_ruffle_player = function() {
+  if (!window.RufflePlayer) {
+    return;
+  }
+
+  let ruffle = window.RufflePlayer.newest();
+  let player = ruffle.createPlayer();
+  let $container = $(".ruffle-container[data-swf]");
+  let src = $container.attr("data-swf");
+  $container.get(0).appendChild(player);
+  player.load(src);
+};
+
 Post.resize_ugoira_controls = function() {
   var $img = $("#image");
   var width = Math.max($img.width(), 350);

app/views/layouts/default.html.erb

@@ -16,7 +16,14 @@
   <% if CurrentUser.user.blacklisted_tags.present? %>
     <meta name="blacklisted-tags" content="<%= CurrentUser.user.blacklisted_tags.gsub(/(?:\r|\n)+/, ",") %>">
   <% end %>
-  <%= javascript_pack_tag "application" %>
+
+  <%# XXX hack to only load Ruffle on Flash posts %>
+  <% if controller_name == "posts" && action_name == "show" && @post.is_flash? %>
+    <%= javascript_pack_tag "application", "flash" %>
+  <% else %>
+    <%= javascript_pack_tag "application" %>
+  <% end %>
+
   <%= stylesheet_pack_tag "application" %>
   <% if CurrentUser.user.custom_style.present? && params.fetch(:css, "true").truthy?  %>
     <%= stylesheet_link_tag custom_style_users_path(md5: Digest::MD5.hexdigest(CurrentUser.user.custom_style)), media: "screen" %>

app/views/posts/partials/show/_flash.html.erb

@@ -1,8 +1,3 @@
-<%= content_tag(:object, :width => post.image_width, :height => post.image_height) do %>
+<div class="ruffle-container" data-swf="<%= post.tagged_file_url %>"></div>
-  <%= tag :params, :name => "movie", :value => post.tagged_file_url %>
-  <%= tag :embed, :src => post.tagged_file_url, :width => post.image_width, :height => post.image_height, :allowScriptAccess => "never" %>
-<% end %>
 
 <p><%= link_to "Save this flash (right click and save)", post.tagged_file_url %></p>
-
-<%= javascript_pack_tag "flash" %>