Clean up histogram'd media enum max values.

media/audio/pulse/pulse_util.cc

Index: media/audio/pulse/pulse_util.cc
diff --git a/media/audio/pulse/pulse_util.cc b/media/audio/pulse/pulse_util.cc
index 96831cfabe3277fd165ec45b92995dad29978d72..fe00e02c8e9522192cb198d1e62ab76133f74888 100644
--- a/media/audio/pulse/pulse_util.cc
+++ b/media/audio/pulse/pulse_util.cc
@@ -41,7 +41,7 @@ pa_channel_position ChromiumToPAChannelPosition(Channels channel) {
       return PA_CHANNEL_POSITION_SIDE_LEFT;
     case SIDE_RIGHT:
       return PA_CHANNEL_POSITION_SIDE_RIGHT;
-    case CHANNELS_MAX:
+    case CHANNELS_HISTOGRAM_MAX:
       return PA_CHANNEL_POSITION_INVALID;
     default:
       NOTREACHED() << "Invalid channel: " << channel;
@@ -86,7 +86,7 @@ pa_channel_map ChannelLayoutToPAChannelMap(ChannelLayout channel_layout) {
   pa_channel_map_init(&channel_map);
 
   channel_map.channels = ChannelLayoutToChannelCount(channel_layout);
-  for (Channels ch = LEFT; ch < CHANNELS_MAX;
+  for (Channels ch = LEFT; ch < CHANNELS_HISTOGRAM_MAX;
        ch = static_cast<Channels>(ch + 1)) {
     int channel_index = ChannelOrder(channel_layout, ch);
     if (channel_index < 0)