Collapse AudioRendererMixer and OnMoreDataResampler into AudioTransform.

media/base/fake_audio_render_callback.h

Index: media/base/fake_audio_render_callback.h
diff --git a/media/base/fake_audio_render_callback.h b/media/base/fake_audio_render_callback.h
index 760e39d6e9039c3fd40bf3aef74d206f6c8f9d1c..5318c99e851313ca998929ec52b236dbbf79fc33 100644
--- a/media/base/fake_audio_render_callback.h
+++ b/media/base/fake_audio_render_callback.h
@@ -5,6 +5,7 @@
 #ifndef MEDIA_BASE_FAKE_AUDIO_RENDER_CALLBACK_H_
 #define MEDIA_BASE_FAKE_AUDIO_RENDER_CALLBACK_H_
 
+#include "media/base/audio_converter.h"
 #include "media/base/audio_renderer_sink.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
@@ -12,7 +13,10 @@ namespace media {
 
 // Fake RenderCallback which will fill each request with a sine wave.  Sine
 // state is kept across callbacks.  State can be reset to default via reset().
-class FakeAudioRenderCallback : public AudioRendererSink::RenderCallback {
+// Also provide an interface to AudioTransformInput.
+class FakeAudioRenderCallback
+    : public AudioRendererSink::RenderCallback,
+      public AudioConverter::InputCallback {
  public:
   // The function used to fulfill Render() is f(x) = sin(2 * PI * x * |step|),
   // where x = [|number_of_frames| * m, |number_of_frames| * (m + 1)] and m =
@@ -22,9 +26,14 @@ class FakeAudioRenderCallback : public AudioRendererSink::RenderCallback {
 
   // Renders a sine wave into the provided audio data buffer.  If |half_fill_|
   // is set, will only fill half the buffer.
-  int Render(AudioBus* audio_bus, int audio_delay_milliseconds) OVERRIDE;
+  virtual int Render(AudioBus* audio_bus,
+                     int audio_delay_milliseconds) OVERRIDE;
   MOCK_METHOD0(OnRenderError, void());
 
+  // AudioTransform::ProvideAudioTransformInput implementation.
+  virtual double ProvideInput(AudioBus* audio_bus,
+                              base::TimeDelta buffer_delay) OVERRIDE;
+
   // Toggles only filling half the requested amount during Render().
   void set_half_fill(bool half_fill) { half_fill_ = half_fill; }
 
@@ -35,11 +44,15 @@ class FakeAudioRenderCallback : public AudioRendererSink::RenderCallback {
   // no Render() call occurred.
   int last_audio_delay_milliseconds() { return last_audio_delay_milliseconds_; }
 
+  // Set volume information used by ProvideAudioTransformInput().
+  void set_volume(double volume) { volume_ = volume; }
+
  private:
   bool half_fill_;
   double x_;
   double step_;
   int last_audio_delay_milliseconds_;
+  double volume_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeAudioRenderCallback);
 };