Revert r95841 due to failing media_unittests on linux_shared bot.

media/base/channel_layout.h

 // Copyright (c) 2011 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.
 
 #ifndef MEDIA_BASE_CHANNEL_LAYOUT_H_
 #define MEDIA_BASE_CHANNEL_LAYOUT_H_
 
-#include "media/base/media_export.h"
-
 enum ChannelLayout {
   CHANNEL_LAYOUT_NONE = 0,
   CHANNEL_LAYOUT_UNSUPPORTED,
 
   // Front C
   CHANNEL_LAYOUT_MONO,
 
   // Front L, Front R
   CHANNEL_LAYOUT_STEREO,
 
@@ skipping 59 matching lines @@
 
 // The channel orderings for each layout as specified by FFmpeg.
 // Values represent the index of each channel in each layout. For example, the
 // left side surround sound channel in FFmpeg's 5.1 layout is in the 5th
 // position (because the order is L, R, C, LFE, LS, RS), so
 // kChannelOrderings[CHANNEL_LAYOUT_5POINT1][SIDE_LEFT] = 4;
 // Values of -1 mean the channel at that index is not used for that layout.
 extern const int kChannelOrderings[CHANNEL_LAYOUT_MAX][CHANNELS_MAX];
 
 // Returns the number of channels in a given ChannelLayout.
-MEDIA_EXPORT int ChannelLayoutToChannelCount(ChannelLayout layout);
+int ChannelLayoutToChannelCount(ChannelLayout layout);
 
 #endif  // MEDIA_BASE_CHANNEL_LAYOUT_H_