Validate cookie values wrapped in double-quotes

Servers sometimes send headers with cookie values that are encapsulated in double-quotes. Dart should validate values surrounded with double-quotes instead of throwing a FormatException.

This addresses Issue #33327 directly. I applied the solution to this problem that was [solved in Go's code base](https://github.com/golang/go/blob/master/src/net/http/cookie.go#L369).

Closes #33765
#33765

GitOrigin-RevId: 99672dd
Change-Id: Ie95a064611b1aa15aea93f5c8d801ecfc7d996c4
Reviewed-on: https://dart-review.googlesource.com/63920
Reviewed-by: Zach Anderson <zra@google.com>
Commit-Queue: Zach Anderson <zra@google.com>

sdk/lib/_http/http_headers.dart

@@ -957,7 +957,7 @@ class _Cookie implements Cookie {
   }
 
   void _validate() {
-    const SEPERATORS = const [
+    const separators = const [
       "(",
       ")",
       "<",
@@ -980,11 +980,15 @@ class _Cookie implements Cookie {
       int codeUnit = name.codeUnits[i];
       if (codeUnit <= 32 ||
           codeUnit >= 127 ||
-          SEPERATORS.indexOf(name[i]) >= 0) {
+          separators.indexOf(name[i]) >= 0) {
         throw new FormatException(
             "Invalid character in cookie name, code unit: '$codeUnit'");
       }
     }
+
+    if (value[0] == '"' && value[value.length - 1] == '"') {
+      value = value.substring(1, value.length - 1);
+    }
     for (int i = 0; i < value.length; i++) {
       int codeUnit = value.codeUnits[i];
       if (!(codeUnit == 0x21 ||

tests/standalone_2/io/http_cookie_test.dart

@@ -58,6 +58,16 @@ void testCookies() {
   });
 }
 
+void testValidateCookieWithDoubleQuotes() {
+  try {
+    Cookie cookie = Cookie('key', '"double-quoted-value"');
+  } catch (e) {
+    Expect.fail("Unexpected error $e.\n"
+        "Unable to parse cookie with value in double-quote characters.");
+  }
+}
+
 void main() {
   testCookies();
+  testValidateCookieWithDoubleQuotes();
 }