Add UMAs for checking header values against RFC 7230 in //net

net/http/http_util.cc

Index: net/http/http_util.cc
diff --git a/net/http/http_util.cc b/net/http/http_util.cc
index f1e5143e701a5334499dccc9a814ae4c96d2023b..16e32b57b9bf39bdccd2c30354773e4e8b173d31 100644
--- a/net/http/http_util.cc
+++ b/net/http/http_util.cc
@@ -346,6 +346,28 @@ bool HttpUtil::IsValidHeaderValue(const std::string& value) {
 }
 
 // static
+bool HttpUtil::IsValidHeaderValueRFC7230(base::StringPiece value) {

[davidben, 2015/09/30 16:38:18]

Optional: Now that you have a base::StringPiece, I think this would be more
readable if you wrote this using those APIs.

if (value.empty())
  return true;

if (IsLWS(value[0]) || IsLWS(value[value.size() - 1]))
  return false;

// Can you just write "for (unsigned char c : value) {"? I'm not
// sure. Did I mention I really hate how C messed up char
// signedness? :-)
for (char c_signed : value) {
  unsigned char c = static_cast<unsigned char>(c_signed);
  if (c == .......)
    return false;
}
return true;

[hiroshige, 2015/12/15 12:00:26]

Done.

+  base::StringPiece::const_iterator value_begin = value.begin();
+  base::StringPiece::const_iterator value_end = value.end();
+
+  // Empty string is a valid header-value.

[davidben, 2015/09/30 16:38:18]

Nit: "This empty string is a valid header-value.

[hiroshige, 2015/12/15 12:00:26]

Done.

+  if (value_begin == value_end)
+    return true;
+
+  // Check leading/trailing whitespaces.
+  if (IsLWS(*value_begin) || IsLWS(*(value_end - 1)))
+    return false;
+
+  // Check each octet is |field-vchar|, |SP| or |HTAB|.
+  for (; value_begin != value_end; ++value_begin) {
+    unsigned char c = *value_begin;
+    if (c == 0x7F || c > 0xFF || (c < 0x20 && c != '\t'))

[davidben, 2015/09/30 16:38:18]

c > 0xFF isn't possible. char's are one byte.

[hiroshige, 2015/12/15 12:00:26]

Done.

+      return false;
+  }
+  return true;
+}
+
+// static
 std::string HttpUtil::StripHeaders(const std::string& headers,
                                    const char* const headers_to_remove[],
                                    size_t headers_to_remove_len) {