Imported Upstream version 5.20.0.180

Former-commit-id: ff953ca879339fe1e1211f7220f563e1342e66cb

mcs/class/System.Net.Http/System.Net.Http/HttpClient.cs

@@ -44,7 +44,7 @@ namespace System.Net.Http
 		long buffer_size;
 		TimeSpan timeout;
 
-#if !XAMARIN_MODERN
+#if !XAMARIN_MODERN && !WASM
 		public HttpClient ()
 			: this (new HttpClientHandler (), true)
 		{
@@ -115,6 +115,8 @@ namespace System.Net.Http
 			if (disposing && !disposed) {
 				disposed = true;
 
+				//We don't use CancelPendingRequests() because we don't want to create new CancellationTokenSource
+				cts.Cancel ();
 				cts.Dispose ();
 			}
 			

mcs/class/System.Net.Http/System.Net.Http/HttpClient.wasm.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+
+namespace System.Net.Http
+{
+    public partial class HttpClient
+    {
+
+        private static Func<HttpMessageHandler> GetHttpMessageHandler;
+
+        public HttpClient()
+            : this(GetDefaultHandler(), true)
+        {
+        }
+
+        static HttpMessageHandler GetDefaultHandler()
+        {
+
+            if (GetHttpMessageHandler == null)
+                return GetFallback("No custom HttpClientHandler registered");
+
+            var handler = GetHttpMessageHandler();
+            if (handler == null)
+                return GetFallback($"Custom HttpMessageHandler is not valid");
+
+            return handler;
+        }
+
+        static HttpMessageHandler GetFallback(string message)
+        {
+            //Console.WriteLine(message + ". Defaulting to System.Net.Http.HttpClientHandler");
+            return new HttpClientHandler();
+        }
+    }
+}

mcs/class/System.Net.Http/wasm_System.Net.Http.dll.sources

@@ -0,0 +1,2 @@
+#include System.Net.Http.dll.sources
+System.Net.Http/HttpClient.wasm.cs