Rewrite std::string("") to std::string(), Linux edition.

media/audio/linux/alsa_output.cc

 // Copyright (c) 2012 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.
 //
 // THREAD SAFETY
 //
 // AlsaPcmOutputStream object is *not* thread-safe and should only be used
 // from the audio thread.  We DCHECK on this assumption whenever we can.
 //
 // SEMANTICS OF Close()
@@ skipping 505 matching lines @@
 
 std::string AlsaPcmOutputStream::FindDeviceForChannels(uint32 channels) {
   // Constants specified by the ALSA API for device hints.
   static const int kGetAllDevices = -1;
   static const char kPcmInterfaceName[] = "pcm";
   static const char kIoHintName[] = "IOID";
   static const char kNameHintName[] = "NAME";
 
   const char* wanted_device = GuessSpecificDeviceName(channels);
   if (!wanted_device)
-    return "";
+    return std::string();
 
   std::string guessed_device;
   void** hints = NULL;
   int error = wrapper_->DeviceNameHint(kGetAllDevices,
                                        kPcmInterfaceName,
                                        &hints);
   if (error == 0) {
     // NOTE: Do not early return from inside this if statement.  The
     // hints above need to be freed.
     for (void** hint_iter = hints; *hint_iter != NULL; hint_iter++) {
@@ skipping 221 matching lines @@
 }
 
 // Changes the AudioSourceCallback to proxy calls to.  Pass in NULL to
 // release ownership of the currently registered callback.
 void AlsaPcmOutputStream::set_source_callback(AudioSourceCallback* callback) {
   DCHECK(IsOnAudioThread());
   source_callback_ = callback;
 }
 
 }  // namespace media