Stop polyfilling CSS variables in GENERIC builds

[Snuffleupagus]

At this point in time, all browsers that we support have native support for CSS variables; please see https://developer.mozilla.org/en-US/docs/Web/CSS/Using_CSS_custom_properties#browser_compatibility and

pdf.js/gulpfile.js

Lines 79 to 91 in 9af8501

	// Default Autoprefixer config used for generic, components, minified-pre
	var AUTOPREFIXER_CONFIG = {
	overrideBrowserslist: [
	"last 2 versions",
	"Chrome >= 49", // Last supported on Windows XP
	"Firefox >= 52", // Last supported on Windows XP
	"Firefox ESR",
	"Safari >= 10",
	"> 0.5%",
	"not IE > 0",
	"not dead",
	],
	};

This reduces the size of the built viewer.css file, in GENERIC builds, from 93 814 to 55 285 bytes (~41 percent).

[Snuffleupagus]

/botio-linux preview

[pdfjsbot]

From: Bot.io (Linux m4)

---

Received

Command cmd_preview from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.67.70.0:8877/37329c6f6939c4b/output.txt

[pdfjsbot]

From: Bot.io (Linux m4)

---

Success

Full output at http://54.67.70.0:8877/37329c6f6939c4b/output.txt

Total script time: 4.31 mins

Published

• Viewer: http://54.67.70.0:8877/37329c6f6939c4b/web/viewer.html
• Viewer (ES5): http://54.67.70.0:8877/37329c6f6939c4b/es5/web/viewer.html

[timvandermeij]

Nice, that's a pretty significant reduction!