MD WebUI: Uglify vulcanized javascript bundles to remove comments/whitespace

We run uglify in 'beautify' mode so that output is still human-readable,
but comments and whitespace are removed. This reduces the size of
resources.pak by 330K.

BUG=629406,638624
NOPRESUBMIT=true # crisper.js
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2257723002
Cr-Commit-Position: refs/heads/master@{#413070}

chrome/browser/resources/vulcanize.py

@@ -85,6 +85,13 @@ def _vulcanize(directory, host, html_in_file, html_out_file='vulcanized.html',
                          '--script-in-head', 'false',
                          '--html', html_out_path,
                          '--js', js_out_path])
+
+    # TODO(tsergeant): Remove when JS resources are minified by default:
+    # crbug.com/619091.
+    _run_cmd(['uglifyjs', js_out_path,
+                         '--beautify', 'indent-level=2,quote_style=3',
+                         '--comments', '/Copyright|license|LICENSE|\<\/?if/',
+                         '--output', js_out_path])
   finally:
     os.remove(tmp.name)
 

docs/vulcanize.md

@@ -12,6 +12,7 @@ Vulcanization currently requires:
 - npm: >= 1.3.10 (can be found with `npm --version`)
 - vulcanize: 1.14.8 (can be found with `vulcanize --version`)
 - crisper: 2.0.1 (can be found with `npm list -g crisper`)
+- uglifyjs: 2.4.10 (can be found with `uglifyjs --version`)
 
 ## Installing required software
 
@@ -30,8 +31,8 @@ Then install the required modules:
 $ npm install -g crisper vulcanize
 ```
 
-Ultimately, all that is required to run this script is that `crisper` and
-`vulcanize` are on your `$PATH`.
+Ultimately, all that is required to run this script is that `crisper`, 'uglify'
+and `vulcanize` are on your `$PATH`.
 
 ## Combining resources with vulcanize