Do not hash default and communications media device ID

content/public/browser/media_device_id.cc

 // Copyright 2013 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 "content/public/browser/media_device_id.h"
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "content/browser/browser_main_loop.h"
 #include "content/browser/renderer_host/media/media_stream_manager.h"
 #include "crypto/hmac.h"
 
 namespace content {
 
+namespace {
+
+const char kDefaultDeviceId[] = "default";

[tommi (sloooow) - chröme, 2015/09/26 09:27:23]

Can we use the constants from media/ instead?
https://code.google.com/p/chromium/codesearch#chromium/src/media/audio/audio_...

[Guido Urdaneta, 2015/09/26 09:48:58]

I originally tried that, but, unfortunaetly, it is forbidden to #include
"media/" in content/public.

Maybe we should also expose these public/content constants and check that they
match the media constants somewhere?

[tommi (sloooow) - chröme, 2015/09/26 10:13:47]

Ah right. I didn't realize we're in public/.  Hmm... it's unfortunate that
content/ can't access media/ for the benefit of content/.  I think the actual
implementation of these methods needs to be moved into content (e.g. under
content/browser/media)

+const char kCommunicationsDeviceId[] = "communications";
+
+bool IsDefaultMediaDeviceID(const std::string& source_id) {
+  return (source_id == kDefaultDeviceId) ||

[tommi (sloooow) - chröme, 2015/09/26 09:27:24]

nit: () not necessary

[Guido Urdaneta, 2015/09/26 09:48:58]

Done.

+         (source_id == kCommunicationsDeviceId);
+}
+
+}  // namespace
+
 std::string GetHMACForMediaDeviceID(const ResourceContext::SaltCallback& sc,
                                     const GURL& security_origin,
                                     const std::string& raw_unique_id) {
+  if (IsDefaultMediaDeviceID(raw_unique_id))
+    return raw_unique_id;
+
   DCHECK(security_origin.is_valid());
   DCHECK(!raw_unique_id.empty());
   crypto::HMAC hmac(crypto::HMAC::SHA256);
   const size_t digest_length = hmac.DigestLength();
   std::vector<uint8> digest(digest_length);
   std::string salt = sc.Run();
   bool result = hmac.Init(security_origin.spec()) &&
       hmac.Sign(raw_unique_id + salt, &digest[0], digest.size());
   DCHECK(result);
   return base::ToLowerASCII(base::HexEncode(&digest[0], digest.size()));
@@ skipping 20 matching lines @@
 
   return manager->TranslateSourceIdToDeviceId(
       content::MEDIA_DEVICE_VIDEO_CAPTURE,
       rc,
       security_origin,
       source_id,
       device_id);
 }
 
 }  // namespace content