Replace deprecated Node Buffer constructor (#3126)

Author: kudlav

platform/node/test/js/map.test.js

@@ -199,7 +199,7 @@ test('Map', function(t) {
             var map = new mbgl.Map(options);
 
             t.throws(function() {
-                map.addImage('foo', new Buffer(''), {
+                map.addImage('foo', Buffer.from(''), {
                     width: 401,
                     height: 400,
                     pixelRatio: 1
@@ -214,7 +214,7 @@ test('Map', function(t) {
             var map = new mbgl.Map(options);
 
             t.throws(function() {
-                map.addImage('foo', new Buffer(''), {
+                map.addImage('foo', Buffer.from(''), {
                     width: 1025,
                     height: 1025,
                     pixelRatio: 1
@@ -230,7 +230,7 @@ test('Map', function(t) {
             var map = new mbgl.Map(options);
 
             t.throws(function() {
-                map.addImage('foo', new Buffer('   '), {
+                map.addImage('foo', Buffer.from('   '), {
                     width: 401,
                     height: 400,
                     pixelRatio: 1
@@ -245,7 +245,7 @@ test('Map', function(t) {
             var map = new mbgl.Map(options);
 
             t.doesNotThrow(function() {
-                map.addImage('foo', new Buffer('    '), {
+                map.addImage('foo', Buffer.from('    '), {
                     width: 1,
                     height: 1,
                     pixelRatio: 1

test/fixtures/sprites/convert_sprite.js

@@ -7,7 +7,7 @@ var zlib = require('zlib');
 var PNG = require('png-js');
 var png = PNG.load('styles/sprites/bright.png');
 png.decodePixels(function(data) {
-    var result = new Buffer(8 + data.length);
+    var result = Buffer.alloc(8 + data.length);
     result.writeUInt32BE(png.width, 0);
     result.writeUInt32BE(png.height, 4);
     data.copy(result, 8);