Clean up histogram'd media enum max values.

media/audio/audio_output_resampler.cc

 // Copyright (c) 2012 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 "media/audio/audio_output_resampler.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/compiler_specific.h"
 #include "base/metrics/histogram.h"
@@ skipping 54 matching lines @@
 
   // Handles resampling, buffering, and channel mixing between input and output
   // parameters.
   AudioConverter audio_converter_;
 
   DISALLOW_COPY_AND_ASSIGN(OnMoreDataConverter);
 };
 
 // Record UMA statistics for hardware output configuration.
 static void RecordStats(const AudioParameters& output_params) {
   UMA_HISTOGRAM_ENUMERATION(

[rileya (GONE FROM CHROMIUM), 2014/01/29 21:12:20]

This isn't actually an enumeration, is there a better way of UMA-ing this?

[Ami GONE FROM CHROMIUM, 2014/01/29 21:29:02]

Sure, you can basically expand the macro.

[rileya (GONE FROM CHROMIUM), 2014/02/05 22:30:05]

I did this, but it seems rather ugly. I think UMA_HISTOGRAM_CUSTOM_COUNTS would
be more appropriate, but I'm unsure if this would still match up with existing
data.

[Ami GONE FROM CHROMIUM, 2014/02/05 22:42:54]

I would not trust myself to verify that by inspection and would have to test it
on all inputs to convince myself it was correct.
Why bother, though?  You can't reduce the # of buckets without messing up
historical data, so what would the gain be?  Just not using "ENUMERATION" for a
non-enum?  Doesn't seem worth it to me.

[rileya (GONE FROM CHROMIUM), 2014/02/06 21:12:40]

Fair enough, so does the current slightly verbose/ugly expanded macro seem
acceptable?

       "Media.HardwareAudioBitsPerChannel", output_params.bits_per_sample(),
       limits::kMaxBitsPerSample);
   UMA_HISTOGRAM_ENUMERATION(
       "Media.HardwareAudioChannelLayout", output_params.channel_layout(),
-      CHANNEL_LAYOUT_MAX);
+      CHANNEL_LAYOUT_MAX + 1);
   UMA_HISTOGRAM_ENUMERATION(

[rileya (GONE FROM CHROMIUM), 2014/01/29 21:12:20]

Same here. More in the Fallback function below.

       "Media.HardwareAudioChannelCount", output_params.channels(),
       limits::kMaxChannels);
 
   AudioSampleRate asr = media::AsAudioSampleRate(output_params.sample_rate());
   if (asr != kUnexpectedAudioSampleRate) {
     UMA_HISTOGRAM_ENUMERATION(
-        "Media.HardwareAudioSamplesPerSecond", asr, kUnexpectedAudioSampleRate);
+        "Media.HardwareAudioSamplesPerSecond", asr, kAudioSampleRateMax + 1);
   } else {
     UMA_HISTOGRAM_COUNTS(
         "Media.HardwareAudioSamplesPerSecondUnexpected",
         output_params.sample_rate());
   }
 }
 
 // Record UMA statistics for hardware output configuration after fallback.
 static void RecordFallbackStats(const AudioParameters& output_params) {
   UMA_HISTOGRAM_BOOLEAN("Media.FallbackToHighLatencyAudioPath", true);
   UMA_HISTOGRAM_ENUMERATION(
       "Media.FallbackHardwareAudioBitsPerChannel",
       output_params.bits_per_sample(), limits::kMaxBitsPerSample);
   UMA_HISTOGRAM_ENUMERATION(
       "Media.FallbackHardwareAudioChannelLayout",
-      output_params.channel_layout(), CHANNEL_LAYOUT_MAX);
+      output_params.channel_layout(), CHANNEL_LAYOUT_MAX + 1);
   UMA_HISTOGRAM_ENUMERATION(
       "Media.FallbackHardwareAudioChannelCount",
       output_params.channels(), limits::kMaxChannels);
 
   AudioSampleRate asr = media::AsAudioSampleRate(output_params.sample_rate());
   if (asr != kUnexpectedAudioSampleRate) {
     UMA_HISTOGRAM_ENUMERATION(
         "Media.FallbackHardwareAudioSamplesPerSecond",
-        asr, kUnexpectedAudioSampleRate);
+        asr, kAudioSampleRateMax);

[Ami GONE FROM CHROMIUM, 2014/01/29 21:29:02]

If you had a PRESUBMIT it would bitch about this.  
Per elsewhere hopefully this can become Max+1.

   } else {
     UMA_HISTOGRAM_COUNTS(
         "Media.FallbackHardwareAudioSamplesPerSecondUnexpected",
         output_params.sample_rate());
   }
 }
 
 // Converts low latency based |output_params| into high latency appropriate
 // output parameters in error situations.
 void AudioOutputResampler::SetupFallbackParams() {
@@ skipping 270 matching lines @@
   if (frames > 0 && frames < dest->frames())
     dest->ZeroFramesPartial(frames, dest->frames() - frames);
   return frames > 0 ? 1 : 0;
 }
 
 void OnMoreDataConverter::OnError(AudioOutputStream* stream) {
   source_callback_->OnError(stream);
 }
 
 }  // namespace media