Fix reading ArrayBuffer into string on older browsers

Android 4.0 doesn't like the `String.fromCharCode.apply` hack.

fetch.js

@@ -178,6 +178,16 @@
     return promise
   }
 
+  function readArrayBufferAsText(buf) {
+    var view = new Uint8Array(buf)
+    var chars = new Array(view.length)
+
+    for (var i = 0; i < view.length; i++) {
+      chars[i] = String.fromCharCode(view[i])
+    }
+    return chars.join('')
+  }
+
   function bufferClone(buf) {
     if (buf.slice) {
       return buf.slice(0)
@@ -252,9 +262,7 @@
       if (this._bodyBlob) {
         return readBlobAsText(this._bodyBlob)
       } else if (this._bodyArrayBuffer) {
-        var view = new Uint8Array(this._bodyArrayBuffer)
-        var str = String.fromCharCode.apply(null, view)
-        return Promise.resolve(str)
+        return Promise.resolve(readArrayBufferAsText(this._bodyArrayBuffer))
       } else if (this._bodyFormData) {
         throw new Error('could not read FormData body as text')
       } else {

test/test.js

@@ -64,7 +64,13 @@ function arrayBufferFromText(text) {
 }
 
 function readArrayBufferAsText(buf) {
-  return String.fromCharCode.apply(null, new Uint8Array(buf))
+  var view = new Uint8Array(buf)
+  var chars = new Array(view.length)
+
+  for (var i = 0; i < view.length; i++) {
+    chars[i] = String.fromCharCode(view[i])
+  }
+  return chars.join('')
 }
 
 var preservedGlobals = {}