feat: change window to self for webworker support

package.json

@@ -44,7 +44,7 @@
     "nodeify": "^1.0.0"
   },
   "devDependencies": {
-    "aegir": "^9.4.0",
+    "aegir": "^10.0.0",
     "benchmark": "^2.1.3",
     "chai": "^3.5.0",
     "pre-commit": "^1.2.2"
@@ -63,4 +63,4 @@
     "Richard Littauer <richard.littauer@gmail.com>",
     "npm-to-cdn-bot (by Forbes Lindesay) <npmcdn-to-unpkg-bot@users.noreply.github.com>"
   ]
-}
+}

src/crypto-sha1-2-browser.js

@@ -1,27 +1,16 @@
-/* global self */
 'use strict'
 
 const nodeify = require('nodeify')
 
 const webCrypto = getWebCrypto()
 
 function getWebCrypto () {
-  let globalContext
-
-  if (typeof window !== 'undefined') {
-    globalContext = window
-  } else if (typeof self !== 'undefined') {
-    globalContext = self
-  } else {
-    return
-  }
-
-  if (globalContext.crypto) {
-    return globalContext.crypto.subtle || globalContext.crypto.webkitSubtle
+  if (self.crypto) {
+    return self.crypto.subtle || self.crypto.webkitSubtle
   }
 
-  if (globalContext.msCrypto) {
-    return globalContext.msCrypto.subtle
+  if (self.msCrypto) {
+    return self.msCrypto.subtle
   }
 }