Refactor the Get*Hardware* routines a bit.

content/renderer/media/audio_device.cc

 // Copyright (c) 2011 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/renderer/media/audio_device.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/message_loop.h"
 #include "base/time.h"
 #include "content/common/child_process.h"
 #include "content/common/media/audio_messages.h"
 #include "content/common/view_messages.h"
 #include "content/renderer/render_thread_impl.h"
 #include "media/audio/audio_util.h"
 
+double AudioHardware::output_sample_rate_ = 0.0;
+double AudioHardware::input_sample_rate_ = 0.0;
+size_t AudioHardware::output_buffer_size_ = 0;
+
+
 AudioDevice::AudioDevice(size_t buffer_size,
                          int channels,
                          double sample_rate,
                          RenderCallback* callback)
     : buffer_size_(buffer_size),
       channels_(channels),
       bits_per_sample_(16),
       sample_rate_(sample_rate),
       callback_(callback),
       audio_delay_milliseconds_(0),
@@ skipping 200 matching lines @@
     // Update the audio-delay measurement then ask client to render audio.
     callback_->Render(audio_data_, buffer_size_, audio_delay_milliseconds_);
 
     // Interleave, scale, and clip to int16.
     media::InterleaveFloatToInt16(audio_data_,
                                   static_cast<int16*>(shared_memory_data()),
                                   buffer_size_);
   }
 }
 
-double AudioDevice::GetAudioHardwareSampleRate() {
-  // Uses cached value if possible.
-  static double hardware_sample_rate = 0;
-  if (!hardware_sample_rate) {
+double AudioHardware::GetOutputSampleRate() {
+  if (!output_sample_rate_) {
     RenderThreadImpl::current()->Send(
-        new ViewHostMsg_GetHardwareSampleRate(&hardware_sample_rate));
+        new ViewHostMsg_GetHardwareSampleRate(&output_sample_rate_));
   }
-  return hardware_sample_rate;
+  return output_sample_rate_;
 }
 
-size_t AudioDevice::GetAudioHardwareBufferSize() {
-  // Uses cached value if possible.
-  static uint32 buffer_size = 0;
+double AudioHardware::GetInputSampleRate() {
+  if (!input_sample_rate_) {
+    RenderThreadImpl::current()->Send(
+        new ViewHostMsg_GetHardwareInputSampleRate(&input_sample_rate_));
+  }
+  return input_sample_rate_;
+}
 
-  if (!buffer_size) {
+size_t AudioHardware::GetOutputBufferSize() {
+  if (!output_buffer_size_) {
+    uint32 buffer_size = 0;
     RenderThreadImpl::current()->Send(
         new ViewHostMsg_GetHardwareBufferSize(&buffer_size));
+    output_buffer_size_ = buffer_size;
   }
 
-  return static_cast<size_t>(buffer_size);
+  return output_buffer_size_;
 }
+
+void AudioHardware::ResetCache() {
+  output_sample_rate_ = 0.0;
+  input_sample_rate_ = 0.0;
+  output_buffer_size_ = 0;
+}