Support floating-point audio output for Linux

media/audio/pulse/pulse_output.cc

Index: media/audio/pulse/pulse_output.cc
diff --git a/media/audio/pulse/pulse_output.cc b/media/audio/pulse/pulse_output.cc
index f86860571a03fca4390c4149704888b5c3630d55..5efa040c0d1b96a712a77cc309badbeef9db4f2a 100644
--- a/media/audio/pulse/pulse_output.cc
+++ b/media/audio/pulse/pulse_output.cc
@@ -12,6 +12,7 @@
 #include "media/audio/audio_device_description.h"
 #include "media/audio/audio_manager_base.h"
 #include "media/audio/pulse/pulse_util.h"
+#include "media/base/audio_sample_types.h"
 
 namespace media {
 
@@ -43,7 +44,14 @@ void PulseAudioOutputStream::StreamRequestCallback(pa_stream* s, size_t len,
 PulseAudioOutputStream::PulseAudioOutputStream(const AudioParameters& params,
                                                const std::string& device_id,
                                                AudioManagerBase* manager)
-    : params_(params),
+    : params_(AudioParameters(params.format(),
+                              params.channel_layout(),
+                              params.sample_rate(),
+                              // Ignore the given bits per sample. We
+                              // want 32 because we're outputting
+                              // floats.
+                              32,
+                              params.frames_per_buffer())),
       device_id_(device_id),
       manager_(manager),
       pa_context_(NULL),
@@ -143,11 +151,9 @@ void PulseAudioOutputStream::FulfillWriteRequest(size_t requested_bytes) {
             frames_filled, audio_bus_->frames() - frames_filled);
       }
 
-      // Note: If this ever changes to output raw float the data must be clipped
-      // and sanitized since it may come from an untrusted source such as NaCl.
       audio_bus_->Scale(volume_);
-      audio_bus_->ToInterleaved(
-          audio_bus_->frames(), params_.bits_per_sample() / 8, buffer);
+      audio_bus_->ToInterleaved<Float32SampleTypeTraits>(
+          audio_bus_->frames(), reinterpret_cast<float*>(buffer));
     } else {
       memset(buffer, 0, bytes_to_fill);
     }