[Blink>TextEncoder] Removed UTF-16 support from TextEncoder API.

third_party/WebKit/LayoutTests/fast/encoding/api/utf-round-trip.html

Index: third_party/WebKit/LayoutTests/fast/encoding/api/utf-round-trip.html
diff --git a/third_party/WebKit/LayoutTests/fast/encoding/api/utf-round-trip.html b/third_party/WebKit/LayoutTests/fast/encoding/api/utf-round-trip.html
index b190fffd161cda862c6562aad8bacce8b5451270..319fb623e5a523564270d4c23a1224f634469eba 100644
--- a/third_party/WebKit/LayoutTests/fast/encoding/api/utf-round-trip.html
+++ b/third_party/WebKit/LayoutTests/fast/encoding/api/utf-round-trip.html
@@ -30,15 +30,31 @@ function makeBatch(cp) {
     return string;
  }
 
+

[jsbell, 2016/05/02 20:20:06]

nit: remove this extra whitespace; one or two blank lines at most.

+
 utf_encodings.forEach(function(encoding) {

[jsbell, 2016/05/02 20:20:06]

Maybe just split this into a test for utf-8 and then ['utf-16le',
'utf-16be'].forEach(...), since there's nothing in common?

[lpan, 2016/05/03 13:42:00]

Acknowledged. Will do once I figure out how to handle utf-16 encoding manually.

[jsbell, 2016/05/03 22:22:48]

function encode_utf16(s, littleEndian) {
  var a = new Uint8Array(s.length * 2), view = new DataView(a.buffer);
  s.split('').forEach(function(c, i) {
    view.setUint16(i * 2, c.charCodeAt(0), littleEndian);
  });
  return a;
}
... although that doesn't force the input to be a USVString so it doesn't behave
identically to the way the encoder used to.

-    test(function() {
-        for (var i = 0; i < 0x10FFFF; i += BATCH_SIZE) {
-            var string = makeBatch(i);
-            var encoded = new TextEncoder(encoding).encode(string);
-            var decoded = new TextDecoder(encoding).decode(encoded);
-            assert_equals(decoded, string);
-        }
-    }, encoding + ' - encode/decode round trip');
+    var utf16_exception;

[jsbell, 2016/05/02 20:20:06]

this is unused - remove?

[lpan, 2016/05/03 13:42:00]

Done.

+    if (encoding == "utf-8") {

[jsbell, 2016/05/02 20:20:06]

nit: prefer ===

[lpan, 2016/05/03 13:42:00]

Acknowledged.

+        test(function() {
+            for (var i = 0; i < 0x10FFFF; i += BATCH_SIZE) {
+                var string = makeBatch(i);
+                var encoded = new TextEncoder(encoding).encode(string);

[jsbell, 2016/05/02 20:20:06]

Don't pass argument to TextEncoder

[lpan, 2016/05/03 13:42:01]

Acknowledged.

+                var decoded = new TextDecoder(encoding).decode(encoded);
+                assert_equals(string, decoded);
+            }
+        }, encoding + ' - encode/decode round trip');
+    }
+    else {

[jsbell, 2016/05/02 20:20:06]

nit: format as `} else {`

[lpan, 2016/05/03 13:42:00]

Acknowledged.

+        test(function() {
+            for (var i = 0; i < 0x10FFFF; i += BATCH_SIZE) {
+                var string = makeBatch(i);
+                var encoded = new TextEncoder(encoding).encode(string);

[jsbell, 2016/05/02 20:20:06]

Since encoding is ignored, how is this test intended to work?
Do you want a manual utf-16 encoder (like the utf-8 one below) instead?

[lpan, 2016/05/03 13:42:00]

This was my (poorly thought out) attempt at showing that a round-trip
encode/decode was no longer possible. With a manual utf-16 encoder, am I
validating that TextDecoder still works with utf-16? If so, could I not just
provide a sample utf-16 string?

[jsbell, 2016/05/03 22:22:48]

Right, it's no longer round-trip, so maybe look to see if utf-16 decode is
exercised elsewhere and if so just remove it here.

From a quick check: it's exercised (with samples) in
imported/web-platform-tests/encoding fairly well, including edge cases. So...
you're probably okay removing it if fixing it up is problematic.

+                var decoded = new TextDecoder(encoding).decode(encoded);
+                assert_not_equals(encoded, decoded);
+            }
+        }, encoding + ' - legacy encoding not supported');    
+    }
+
 });
 
 
@@ -61,7 +77,7 @@ test(function() {
     for (var i = 0; i < 0x10FFFF; i += BATCH_SIZE) {
         var string = makeBatch(i);
         var expected = encode_utf8(string);
-        var actual = new TextEncoder('UTF-8').encode(string);
+        var actual = new TextEncoder().encode(string);
         assert_array_equals(actual, expected);
     }
 }, 'UTF-8 encoding (compare against unescape/encodeURIComponent)');
@@ -71,7 +87,7 @@ test(function() {
         var string = makeBatch(i);
         var encoded = encode_utf8(string);
         var expected = decode_utf8(encoded);
-        var actual = new TextDecoder('UTF-8').decode(new Uint8Array(encoded));
+        var actual = new TextDecoder().decode(new Uint8Array(encoded));
         assert_equals(actual, expected);
     }
 }, 'UTF-8 decoding (compare against decodeURIComponent/escape)');