Ignore non-ASCII headers in the mimeHandlerPrivate API.

extensions/browser/api/mime_handler_private/mime_handler_private.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/browser/api/mime_handler_private/mime_handler_private.h"
 
+#include "base/strings/string_util.h"
 #include "content/public/browser/stream_handle.h"
 #include "content/public/browser/stream_info.h"
 #include "extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.h"
 #include "extensions/common/constants.h"
 #include "net/http/http_response_headers.h"
 #include "third_party/mojo/src/mojo/public/cpp/bindings/map.h"
 
 namespace extensions {
 namespace {
 
 mojo::Map<mojo::String, mojo::String> CreateResponseHeadersMap(
     const net::HttpResponseHeaders* headers) {
   std::map<std::string, std::string> result;
   if (!headers)
     return mojo::Map<mojo::String, mojo::String>::From(result);
 
   void* iter = nullptr;
   std::string header_name;
   std::string header_value;
   while (headers->EnumerateHeaderLines(&iter, &header_name, &header_value)) {
+    // mojo strings must be UTF-8 and headers might not be, so drop any headers
+    // that aren't ASCII. The PDF plugin does not use any headers with non-ASCII
+    // names and non-ASCII values are never useful for the headers the plugin
+    // does use.

[raymes, 2015/04/21 01:00:07]

What would be the correct fix? Should we file a bug in case this has an effect
on other users of MimeHandlerView?

[Sam McNally, 2015/04/21 03:18:55]

Added a TODO and mentioned it in the mojom and idl.

+    if (!base::IsStringASCII(header_name) || !base::IsStringASCII(header_value))
+      continue;
     auto& current_value = result[header_name];
     if (!current_value.empty())
       current_value += ", ";
     current_value += header_value;
   }
   return mojo::Map<mojo::String, mojo::String>::From(result);
 }
 
 }  // namespace
 
@@ skipping 53 matching lines @@
   const content::StreamInfo* info = stream.stream_info();
   result->mime_type = info->mime_type;
   result->original_url = info->original_url.spec();
   result->stream_url = info->handle->GetURL().spec();
   result->response_headers =
       extensions::CreateResponseHeadersMap(info->response_headers.get());
   return result.Pass();
 }
 
 }  // namespace mojo