Editing Sam's downloads page

src/site/_includes/downloads/_windows_section.html

+## Download Dart
+
+The Dart Editor bundle is the recommended way to get started with Dart on
+Windows. When you download the Dart Editor bundle, you get everything you need
+to create, edit, test, and build both web-based and server-side applications.
+
+{% include downloads/_dart-editor.html buttonclass="btn-primary" %}
+
+The Dart Editor bundle includes:
+
+* [Dart Editor](/tools/editor/):
+  A powerful tool for editing, debugging, and running Dart
+  applications.
+* [Dartium](/tools/dartium/):
+  A special version of Chromium that includes the Dart VM. You can
+  use Dartium to test and debug your Dart web applications.
+* [Dart SDK](/tools/sdk/):
+  The Dart VM, libraries, and command-line tools such as
+  [dart](/tools/dart-vm/),
+  [dart2js](/tools/dart2js/),
+  [dartanalyzer](/tools/analyzer/),
+  [pub](/tools/pub/), and
+  [docgen](docgen/).
+
+
+## Or download just what you need
+
+At a minimum, you need the Dart SDK.
+
+### Download the Dart SDK
+
+<p class="os-choices">
+{% include downloads/_sdk.html buttonclass="btn btn-primary btn-lg" %}
+</p>
+
+### Download Dartium
+
+If you're writing a web app,
+we recommend downloading Dartium.
+Dartium is a special build of Chromium that includes a Dart VM
+so that you can test and debug your web app without first
+compiling it to JavaScript.
+
+{% include downloads/_dartium.html buttonclass="btn btn-primary btn-lg download-btn" %}
+
+The Dartium binary expires after 12 weeks.  When that happens, you need to
+download a new copy to continue using Dartium.