Improve MidiManagerAlsa manufacturer reporting

media/midi/midi_manager_alsa.h

Index: media/midi/midi_manager_alsa.h
diff --git a/media/midi/midi_manager_alsa.h b/media/midi/midi_manager_alsa.h
index cbe03c5fee776a69e1ec715e40a71a7edd936c1e..d75b47e48baf9b5b1d71a3566e8d0a0f86efdbd2 100644
--- a/media/midi/midi_manager_alsa.h
+++ b/media/midi/midi_manager_alsa.h
@@ -10,14 +10,19 @@
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread.h"
 #include "media/midi/midi_manager.h"
 
+#if defined(USE_UDEV)
+#include "device/udev_linux/scoped_udev.h"
+#endif  // defined(USE_UDEV)
+
 namespace media {
 
-class MidiManagerAlsa : public MidiManager {
+class MEDIA_EXPORT MidiManagerAlsa : public MidiManager {
  public:
   MidiManagerAlsa();
   ~MidiManagerAlsa() override;
@@ -30,6 +35,9 @@ class MidiManagerAlsa : public MidiManager {
                             double timestamp) override;
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(MidiManagerAlsaTest, ExtractManufacturer);
+  FRIEND_TEST_ALL_PREFIXES(MidiManagerAlsaTest, UdevEscape);
+
   // An internal callback that runs on MidiSendThread.
   void SendMidiData(uint32 port_index,
                     const std::vector<uint8>& data);
@@ -37,6 +45,17 @@ class MidiManagerAlsa : public MidiManager {
   void EventReset();
   void EventLoop();
 
+  // Extracts the manufacturer using heuristics and a variety of sources.
+  static std::string ExtractManufacturer(
+      const std::string& udev_id_vendor_enc,
+      const std::string& udev_id_vendor_id,
+      const std::string& udev_id_vendor_from_database,
+      const std::string& alsa_name,
+      const std::string& alsa_longname);
+
+  // Decodes just \xXX in strings.
+  static std::string UnescapeUdev(const std::string& s);
+
   // Alsa seq handles.
   snd_seq_t* in_client_;
   snd_seq_t* out_client_;
@@ -55,6 +74,11 @@ class MidiManagerAlsa : public MidiManager {
   typedef std::vector<snd_midi_event_t*> EncoderList;
   EncoderList encoders_;
 
+  // udev, for querying hardware devices.
+#if defined(USE_UDEV)
+  device::ScopedUdevPtr udev_;
+#endif  // defined(USE_UDEV)
+
   base::Thread send_thread_;
   base::Thread event_thread_;