Escape non-ASCII response headers.

Response headers that are not valid UTF-8 can't be stored in a
base::StringValue, which is always a UTF-8 string, so escape any non-ASCII
values to be safe. This prevents a DCHECK when dev tools' network request
inspector is open and we receive these headers.

BUG=299880

Review URL: https://codereview.chromium.org/453483002

Cr-Commit-Position: refs/heads/master@{#288357}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288357 0039d316-1c4b-4281-b951-d872f2087c98

net/http/http_response_headers.cc

@@ -1355,9 +1355,12 @@ base::Value* HttpResponseHeaders::NetLogCallback(
   std::string value;
   while (EnumerateHeaderLines(&iterator, &name, &value)) {
     std::string log_value = ElideHeaderValueForNetLog(log_level, name, value);
+    std::string escaped_name = EscapeNonASCII(name);
+    std::string escaped_value = EscapeNonASCII(log_value);
     headers->Append(
       new base::StringValue(
-          base::StringPrintf("%s: %s", name.c_str(), log_value.c_str())));
+          base::StringPrintf("%s: %s", escaped_name.c_str(),
+                             escaped_value.c_str())));
   }
   dict->Set("headers", headers);
   return dict;