Remove extra source map file + write source maps only if they are enabled (webpack#453)

* chore: Eliminate convert-source-map

The needed functionality has been extracted to a function.

* fix: Write sourcemaps only if `sourceMap` is enabled

Author: bebraw

lib/convert-source-map.js

@@ -3,13 +3,13 @@
 	Author Tobias Koppers @sokra
 */
 // css base code, injected by the css-loader
-module.exports = function() {
+module.exports = function(useSourceMap) {
 	var list = [];
 
 	// return the list of modules as css string
 	list.toString = function toString() {
 		return this.map(function (item) {
-			var content = cssWithMappingToString(item);
+			var content = cssWithMappingToString(item, useSourceMap);
 			if(item[2]) {
 				return "@media " + item[2] + "{" + content + "}";
 			} else {
@@ -47,16 +47,29 @@ module.exports = function() {
 	return list;
 };
 
-function cssWithMappingToString(item) {
+function cssWithMappingToString(item, useSourceMap) {
 	var content = item[1] || '';
 	var cssMapping = item[3];
 	if (!cssMapping) {
 		return content;
 	}
-	var convertSourceMap = require('./convert-source-map');
-	var sourceMapping = convertSourceMap.fromObject(cssMapping).toComment({multiline: true});
-	var sourceURLs = cssMapping.sources.map(function (source) {
-		return '/*# sourceURL=' + cssMapping.sourceRoot + source + ' */'
-	});
-	return [content].concat(sourceURLs).concat([sourceMapping]).join('\n');
+
+	if (useSourceMap) {
+		var sourceMapping = toComment(cssMapping);
+		var sourceURLs = cssMapping.sources.map(function (source) {
+			return '/*# sourceURL=' + cssMapping.sourceRoot + source + ' */'
+		});
+
+		return [content].concat(sourceURLs).concat([sourceMapping]).join('\n');
+	}
+
+	return [content].join('\n');
+}
+
+// Adapted from convert-source-map (MIT)
+function toComment(sourceMap) {
+  var base64 = new Buffer(JSON.stringify(sourceMap)).toString('base64');
+  var data = 'sourceMappingURL=data:application/json;charset=utf-8;base64,' + base64;
+
+  return '/*# ' + data + ' */';
 }

lib/css-base.js

@@ -108,7 +108,9 @@ module.exports = function(content, map) {
 		}
 
 		// embed runtime
-		callback(null, "exports = module.exports = require(" + loaderUtils.stringifyRequest(this, require.resolve("./css-base.js")) + ")();\n" +
+		callback(null, "exports = module.exports = require(" +
+			loaderUtils.stringifyRequest(this, require.resolve("./css-base.js")) +
+			")(" + query.sourceMap + ");\n" +
 			"// imports\n" +
 			importJs + "\n\n" +
 			"// module\n" +

lib/loader.js

@@ -35,7 +35,7 @@ describe("css-base", function() {
 			"@media screen{body { a: 1; }}");
 	});
 	it("should toString with source mapping", function() {
-		var m = base();
+		var m = base(true);
 		m.push([1, "body { a: 1; }", "", {
 			file: "test.scss",
 			sources: [