Add UMA metrics for ffmpeg color ranges.

media/base/video_frame.h

 // 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.
 
 #ifndef MEDIA_BASE_VIDEO_FRAME_H_
 #define MEDIA_BASE_VIDEO_FRAME_H_
 
 #include "base/callback.h"
 #include "base/md5.h"
 #include "base/memory/shared_memory.h"
@@ skipping 21 matching lines @@
 
     kYPlane = 0,
     kUPlane = 1,
     kVPlane = 2,
     kAPlane = 3,
   };
 
   // Surface formats roughly based on FOURCC labels, see:
   // http://www.fourcc.org/rgb.php
   // http://www.fourcc.org/yuv.php
+  // Logged to UMA, so never reuse values.
   enum Format {
     INVALID = 0,  // Invalid format value.  Used for error reporting.
     RGB32 = 4,  // 32bpp RGB packed with extra byte 8:8:8
     YV12 = 6,  // 12bpp YVU planar 1x1 Y, 2x2 VU samples
     YV16 = 7,  // 16bpp YVU planar 1x1 Y, 2x1 VU samples
     EMPTY = 9,  // An empty frame.
     I420 = 11,  // 12bpp YVU planar 1x1 Y, 2x2 UV samples.
     NATIVE_TEXTURE = 12,  // Native texture.  Pixel-format agnostic.
 #if defined(GOOGLE_TV)
     HOLE = 13,  // Hole frame.
 #endif
     YV12A = 14,  // 20bpp YUVA planar 1x1 Y, 2x2 VU, 1x1 A samples.
+    FORMAT_HISTOGRAM_MAX,  // Must be greater than all other formats.

[scherkus (not reviewing), 2013/10/30 19:37:06]

since we don't prefix the other enums here with FORMAT_ (because they're already
prefixed via VideoFrame::) we can use "HISTOGRAM_MAX"

   };
 
   // Returns the name of a Format as a string.
   static std::string FormatToString(Format format);
 
   // This class calls the TextureNoLongerNeededCallback when the last reference
   // on the class is destroyed. The VideoFrame holds a reference to the mailbox
   // but anyone else who queries the mailbox should also hold a reference while
   // it is uses the mailbox, to ensure it remains valid. When finished with the
   // mailbox, call Return() with a new sync point, to ensure the mailbox remains
@@ skipping 226 matching lines @@
   base::Closure no_longer_needed_cb_;
 
   base::TimeDelta timestamp_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VideoFrame);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_FRAME_H_