Make AudioParameters a class instead of a struct

content/browser/renderer_host/render_message_filter.h

Index: content/browser/renderer_host/render_message_filter.h
diff --git a/content/browser/renderer_host/render_message_filter.h b/content/browser/renderer_host/render_message_filter.h
index 22f66184579938309c6a76ae7cf3769dc1f3a1e3..91083e6d44aaab46b02bcf2c1c9c3fb0a8103477 100644
--- a/content/browser/renderer_host/render_message_filter.h
+++ b/content/browser/renderer_host/render_message_filter.h
@@ -21,6 +21,7 @@
 #include "build/build_config.h"
 #include "content/browser/renderer_host/resource_dispatcher_host.h"
 #include "content/public/browser/browser_message_filter.h"
+#include "media/base/channel_layout.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPopupType.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/surface/transport_dib.h"
@@ -173,7 +174,7 @@ class RenderMessageFilter : public content::BrowserMessageFilter {
   void OnGetHardwareBufferSize(uint32* buffer_size);
   void OnGetHardwareInputSampleRate(double* sample_rate);
   void OnGetHardwareSampleRate(double* sample_rate);
-  void OnGetHardwareInputChannelCount(uint32* channels);
+  void OnGetHardwareInputChannelLayout(ChannelLayout* layout);
 
   // Used to ask the browser to allocate a block of shared memory for the
   // renderer to send back data in, since shared memory can't be created