Add histogram entry for GpuVideoDecoder errors.

media/video/video_decode_accelerator.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_VIDEO_VIDEO_DECODE_ACCELERATOR_H_
 #define MEDIA_VIDEO_VIDEO_DECODE_ACCELERATOR_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 71 matching lines @@
     ILLEGAL_STATE = 1,
     // Invalid argument was passed to an API method.
     INVALID_ARGUMENT,
     // Encoded input is unreadable.
     UNREADABLE_INPUT,
     // A failure occurred at the browser layer or one of its dependencies.
     // Examples of such failures include GPU hardware failures, GPU driver
     // failures, GPU library failures, browser programming errors, and so on.
     PLATFORM_FAILURE,
     // Largest used enum. This should be adjusted when new errors are added.
-    LARGEST_ERROR_ENUM,
+    ERROR_MAX = PLATFORM_FAILURE,
   };
 
   // Config structure contains parameters required for the VDA initialization.
   struct MEDIA_EXPORT Config {
     enum { kNoSurfaceID = SurfaceManager::kNoSurfaceID };
 
     Config() = default;
     Config(VideoCodecProfile profile);
     Config(const VideoDecoderConfig& video_decoder_config);
 
@@ skipping 154 matching lines @@
 // Specialize std::default_delete so that scoped_ptr<VideoDecodeAccelerator>
 // uses "Destroy()" instead of trying to use the destructor.
 template <>
 struct MEDIA_EXPORT default_delete<media::VideoDecodeAccelerator> {
   void operator()(media::VideoDecodeAccelerator* vda) const;
 };
 
 }  // namespace std
 
 #endif  // MEDIA_VIDEO_VIDEO_DECODE_ACCELERATOR_H_