Merge pull request #113 from Unity-Technologies/siyaoH/1.17/android

file load

Samples/UIWidgetsSamples_2019_4/Assets/Script/ImageTest.cs

             public override Widget build(BuildContext context)
             {
                 return new WidgetsApp(
+                    color: Color.white,
                     home: new ExampleApp(),
                     pageRouteBuilder: (settings, builder) =>
                         new PageRouteBuilder(

com.unity.uiwidgets/Runtime/painting/image_provider.cs

         Future<Codec> _loadAsync(FileImage key, DecoderCallback decode) {
 #if UNITY_ANDROID && !UNITY_EDITOR
             var path = Path.Combine(Application.streamingAssetsPath, key.file);
-            WWW unpackerWWW = new WWW(Path.Combine(Application.streamingAssetsPath, key.file));
+#else
+            var path = "file://" + Path.Combine(Application.streamingAssetsPath, key.file);
+#endif
+            WWW unpackerWWW = new WWW(path);
-            byte[] bytes = unpackerWWW.bytes;
-#else
-            byte[] bytes = File.ReadAllBytes(Path.Combine(Application.streamingAssetsPath, key.file));
-#endif
-            if (bytes.Length > 0) {
-                return decode(bytes);
+            if (unpackerWWW.bytes.Length > 0) {
+                return decode(unpackerWWW.bytes);
             }
 
             throw new Exception("not loaded");