Remove unnecassary parameter "sampleRate" for loadAudioResource().

content/renderer/media/audio_decoder.h

 // 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.
 
 #ifndef CONTENT_RENDERER_MEDIA_AUDIO_DECODER_H_
 #define CONTENT_RENDERER_MEDIA_AUDIO_DECODER_H_
 
 #include "base/basictypes.h"
 
 namespace blink { class WebAudioBus; }
 
 namespace content {
 
 // Decode in-memory audio file data.
 bool DecodeAudioFileData(blink::WebAudioBus* destination_bus, const char* data,
-                         size_t data_size, double sample_rate);
+                         size_t data_size);
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_DECODER_H_