Use larger buffer sizes for lower power on Linux.

media/audio/cras/audio_manager_cras.cc

Index: media/audio/cras/audio_manager_cras.cc
diff --git a/media/audio/cras/audio_manager_cras.cc b/media/audio/cras/audio_manager_cras.cc
index ee7cc9cab0f315690e302e9bf96e07f3b7d0a485..53f36abb920f5ed195a7b7b219852f7784c6af16 100644
--- a/media/audio/cras/audio_manager_cras.cc
+++ b/media/audio/cras/audio_manager_cras.cc
@@ -30,6 +30,10 @@ static const int kMaxOutputStreams = 50;
 // Default sample rate for input and output streams.
 static const int kDefaultSampleRate = 48000;
 
+// Define bounds for the output buffer size.
+static const int kMinimumOutputBufferSize = 512;
+static const int kMaximumOutputBufferSize = 8192;
+
 bool AudioManagerCras::HasAudioOutputDevices() {
   return true;
 }
@@ -103,11 +107,9 @@ AudioParameters AudioManagerCras::GetPreferredOutputStreamParameters(
     const AudioParameters& input_params) {
   // TODO(tommi): Support |output_device_id|.
   DLOG_IF(ERROR, !output_device_id.empty()) << "Not implemented!";
-  static const int kDefaultOutputBufferSize = 512;
-
   ChannelLayout channel_layout = CHANNEL_LAYOUT_STEREO;
   int sample_rate = kDefaultSampleRate;
-  int buffer_size = kDefaultOutputBufferSize;
+  int buffer_size = kMinimumOutputBufferSize;
   int bits_per_sample = 16;
   int input_channels = 0;
   if (input_params.IsValid()) {
@@ -115,7 +117,9 @@ AudioParameters AudioManagerCras::GetPreferredOutputStreamParameters(
     bits_per_sample = input_params.bits_per_sample();
     channel_layout = input_params.channel_layout();
     input_channels = input_params.input_channels();
-    buffer_size = input_params.frames_per_buffer();
+    buffer_size =
+        std::min(kMaximumOutputBufferSize,
+                 std::max(buffer_size, input_params.frames_per_buffer()));
   }
 
   int user_buffer_size = GetUserBufferSize();