Vulcanize new Material Design downloads UI

chrome/browser/resources/md_downloads/vulcanize_readme.md

+# Vulcanizing Material Design downloads
+
+`vulcanize` is an npm module used to combine resources.  In order to make the
+Material Design downloads page sufficiently fast, we run vulcanize on the source
+files to combine them and reduce blocking load/parse time.
+
+## Required software
+
+Vulcanization currently requires:
+- node.js: v0.10.25 (can be found with `node --version`)
+- npm: 1.3.10 (can be found with `npm --version`)
+- vulcanize: 1.12.3 (can be found with `vulcanize --version`)
+- crisper: 1.0.7 (can be found with `npm info crisper`)
+
+## Installing required software
+
+For instructions on installing node and npm, see
+[here](https://docs.npmjs.com/getting-started/installing-node).
+
+Once you've installed npm, you can get `crisper` and `vulcanize` via:
+
+```bash
+$ sudo npm install -g crisper vulcanize
+```
+
+## Combining resources with vulcanize
+
+To combine all the CSS/HTML/JS for the downloads page to make it production
+fast, you can run the commands:
+
+```bash
+$ chrome/browser/resources/md_downloads/vulcanize.py  # from src/
+```
+
+This should overwrite the following files:
+
+- chrome/browser/resources/md_downloads/
+ - vulcanized.html (all <link rel=import> and stylesheets inlined)
+ - crisper.js (all JavaScript, extracted from vulcanized.html)
+
+## Testing downloads without vulcanizing
+
+If you're locally working on the downloads page, you can simply load this URL to
+bypass the vulcanized version: `chrome://downloads/dev.html`