Support IPv6 literals in KURL::SetHostAndPort

KURL::SetHostAndPort would corrupt IPv6 literals because they contain
":" characters. Make it check for "[]" characters and use the first ":"
after an IPv6 address as the start of the port number if one is present.

Fixed: 1012416
Change-Id: If07a671b48c8c1b24b16883fb9072a86b0de7ebc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1871449
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Adam Rice <ricea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710668}

url/resources/setters_tests.json

@@ -686,6 +686,17 @@
                 "port": "2"
             }
         },
+        {
+            "comment": "IPv6 literal address with port, crbug.com/1012416",
+            "href": "http://example.net",
+            "new_value": "[2001:db8::2]:4002",
+            "expected": {
+                "href": "http://[2001:db8::2]:4002/",
+                "host": "[2001:db8::2]:4002",
+                "hostname": "[2001:db8::2]",
+                "port": "4002"
+             }
+        },
         {
             "comment": "Default port number is removed",
             "href": "http://example.net",