[MIGRATED] Make deprecation warnings on XHR's setRequestHeader more accurate

Source/core/frame/UseCounter.cpp

Index: Source/core/frame/UseCounter.cpp
diff --git a/Source/core/frame/UseCounter.cpp b/Source/core/frame/UseCounter.cpp
index 2c8a68fd0d79a79c00af42b6df260495b55e3ab1..95ab2eae58ab1a256ae34ddf73be825d5aba3238 100644
--- a/Source/core/frame/UseCounter.cpp
+++ b/Source/core/frame/UseCounter.cpp
@@ -955,7 +955,10 @@ String UseCounter::deprecationMessage(Feature feature)
         return "Request.context is deprecated and will be removed in M46 (see: https://www.chromestatus.com/feature/5534702526005248).";
 
     case HeaderValueNotMatchingRFC7230:
-        return "Header values not matching to RFC 7230, will be deprecated (see: https://www.chromestatus.com/feature/6457425448140800).";
+        return "Header values not matching to RFC 7230 (containing invalid octets). We are experimenting whether such header values can be deprecated (see: https://www.chromestatus.com/feature/6457425448140800).";

[tyoshino (SeeGerritForStatus), 2015/09/25 13:01:35]

"Found a header value that doesn't match the field-content token production
(containing invalid octets. see RFC 7230)."

and, how about explaining what's actually planned instead of "deprecate"? E.g.

'... we can throw for such header values"

[hiroshige, 2015/09/29 05:19:09]

Done.

+
+    case XHRSetRequestHeaderAffectedByNormalize:
+        return "setRequestHeader() affected by header value normalization (header values with leading/trailing whitespaces). We are experimenting whether such whitespaces can be stripped according to the latest spec (see: https://www.chromestatus.com/feature/6457425448140800).";

[tyoshino (SeeGerritForStatus), 2015/09/25 13:01:35]

According to the Fetch Standard, setRequestHeader() must strip leading/trailing
whitespaces, but it doesn't currently. We are experimenting whether we can make
it conform to the spec (see ...). This script will be affected by the change.

[hiroshige, 2015/09/29 05:19:09]

Done.

 
     // Features that aren't deprecated don't have a deprecation message.
     default: