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

ppapi/proxy/audio_input_resource.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.
 
 #include "ppapi/proxy/audio_input_resource.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "ipc/ipc_platform_file.h"
 #include "media/audio/audio_parameters.h"
@@ skipping 199 matching lines @@
 
 void AudioInputResource::SetStreamInfo(
     base::SharedMemoryHandle shared_memory_handle,
     size_t shared_memory_size,
     base::SyncSocket::Handle socket_handle) {
   socket_.reset(new base::CancelableSyncSocket(socket_handle));
   shared_memory_.reset(new base::SharedMemory(shared_memory_handle, false));
   shared_memory_size_ = shared_memory_size;
 
   if (!shared_memory_->Map(shared_memory_size_)) {
-    PpapiGlobals::Get()->LogWithSource(pp_instance(), PP_LOGLEVEL_WARNING, "",
+    PpapiGlobals::Get()->LogWithSource(
+        pp_instance(),
+        PP_LOGLEVEL_WARNING,
+        std::string(),
         "Failed to map shared memory for PPB_AudioInput_Shared.");
   }
 
   // There is a pending capture request before SetStreamInfo().
   if (capturing_) {
     // Set |capturing_| to false so that the state looks consistent to
     // StartCapture(), which will reset it to true.
     capturing_ = false;
     StartCapture();
   }
@@ skipping 36 matching lines @@
     // While closing the stream, we may receive buffers whose size is different
     // from |data_buffer_size|.
     CHECK_LE(buffer->params.size, data_buffer_size);
     if (buffer->params.size > 0)
       audio_input_callback_(&buffer->audio[0], buffer->params.size, user_data_);
   }
 }
 
 }  // namespace proxy
 }  // namespace ppapi