chrome://plugins Mojo-ification part 2/2, populating the page.

chrome/browser/ui/webui/plugins/plugins.mojom

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 struct MimeType {
   string description;
-  array<string> file_extensions;
+  array<string> fileExtensions;
   string mime_type;
 };
 
 struct PluginFile {
   string description;
   string enabled_mode;
   array<MimeType> mime_types;
   string name;
   string path;
   string type;
   string version;
 };
 
 struct PluginData {
   bool always_allowed;
   string description;
   string enabled_mode;
   string id;
   string name;
   string version;
   array<PluginFile> plugin_files;

[sky, 2016/01/20 19:23:08]

Arrays and other non-POD types support null. When you declare an array like it
means the array is never null (an error is generated by bindings code if you
attempt to send a null). If you create an array like this:

  mojo::Array<MimeTypePtr> mime_types;

it's null. Instead if you do:

  mojo::Array<MimeTypePtr> mime_types(0u);

it isn't null. Adding an element to the array implicitly makes it non-null.

If you really want to allow for a null array than you use ?, eg:
array<PluginFile>? plugin_files;

I mention this as a handful of places in your patch you might end up creating an
array as null.

 };
 
 interface PluginsHandlerMojo {
-  GetPluginsData() => (array<PluginData> plugins_data);
+  GetPluginsData() => (array<PluginData> plugins);
   GetShowDetails() => (bool show_details);
   SaveShowDetailsToPrefs(bool details_mode);
   SetPluginAlwaysAllowed(string plugin, bool allowed);
   SetPluginEnabled(string plugin_path, bool enable);
   SetPluginGroupEnabled(string group_name, bool enable);
 };