Add CSS AutoPrefixer (#5148)

* Added CSS autoprefixer as 'less-plugin-autoprefix'

* Change supported iOS versions to 9+

build/style-compiler/NodeRunner.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Diagnostics;
 using System.IO;
+using Newtonsoft.Json;
 
 namespace StyleCompiler
 {
@@ -11,7 +12,13 @@ static class NodeRunner
 
         public static string CompileLess(string less)
         {
-            return RunExternalApp(ResolveNodeToolPath("node"), "node_modules/less/bin/lessc -", Utils.GetRepoRootPath(), less);
+            return RunExternalApp(ResolveNodeToolPath("node"), $"node_modules/less/bin/lessc --autoprefix=\"{ReadBrowsersList()}\" -", Utils.GetRepoRootPath(), less);
+        }
+
+        static string ReadBrowsersList()
+        {
+            dynamic manifest = JsonConvert.DeserializeObject(File.ReadAllText(Path.Combine(Utils.GetRepoRootPath(), "package.json")));
+            return string.Join(",", manifest["browserslist"]);
         }
 
         static string RunExternalApp(string path, string arguments, string workingDirectory, string stdIn)

package.json

@@ -71,6 +71,7 @@
     "knockout": "^3.4.2",
     "lazypipe": "^1.0.1",
     "less": "^2.7.1",
+    "less-plugin-autoprefix": "^2.0.0",
     "lint-staged": "^3.4.0",
     "merge-stream": "^1.0.0",
     "mustache": "2.3.0",
@@ -104,5 +105,11 @@
     "dev": "gulp dev",
     "test-env": "node testing/launch"
   },
+  "browserslist": [
+    "last 2 versions",
+    "ios > 8",
+    "ie > 10",
+    "> 1%"
+  ],
   "pre-commit": "lint-staged"
 }