Add U+2800 to URL unescape banned list

U+2800 (BRAILLE PATTERN BLANK) isn't in the WSpace or
Formatting/Invisibles sets, but should be treated like a space for
purposes of unescaping.

Bug: 1068531
Change-Id: I151f7c803898bc86d81570a93fbe682daf1cca86
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2147477Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Christopher Thompson <cthomp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758627}

net/base/escape.cc

@@ -240,6 +240,9 @@ bool ShouldUnescapeCodePoint(UnescapeRule::Type rules, uint32_t code_point) {
       code_point == 0x202F ||  // NARROW NO-BREAK SPACE      (%E2%80%AF)
       code_point == 0x205F ||  // MEDIUM MATHEMATICAL SPACE  (%E2%81%9F)
       code_point == 0x3000 ||  // IDEOGRAPHIC SPACE          (%E3%80%80)
+      // U+2800 is rendered as a space, but is not considered whitespace (see
+      // crbug.com/1068531).
+      code_point == 0x2800 ||  // BRAILLE PATTERN BLANK      (%E2%A0%80)
 
       // Default Ignorable ([:Default_Ignorable_Code_Point=Yes:]) and Format
       // characters ([:Cf:]) are also banned (see crbug.com/824715).

net/base/escape_unittest.cc

@@ -203,6 +203,7 @@ TEST(EscapeTest, UnescapeURLComponent) {
        "(%E2%80%89)(%E2%80%8A)(%E2%80%A8)(%E2%80%A9)"},
       {"(%E2%80%AF)(%E2%81%9F)(%E3%80%80)", UnescapeRule::NORMAL,
        "(%E2%80%AF)(%E2%81%9F)(%E3%80%80)"},
+      {"(%E2%A0%80)", UnescapeRule::NORMAL, "(%E2%A0%80)"},
 
       // Default Ignorable and Formatting characters should not be unescaped.
       {"(%E2%81%A5)(%EF%BF%B0)(%EF%BF%B8)", UnescapeRule::NORMAL,