Add a histogram for video decoder fallback.

media/filters/decoder_stream.cc

 // Copyright 2014 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/filters/decoder_stream.h"
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/debug/trace_event.h"
 #include "base/location.h"
 #include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/single_thread_task_runner.h"
 #include "media/base/audio_decoder.h"
 #include "media/base/bind_to_current_loop.h"
 #include "media/base/decoder_buffer.h"
 #include "media/base/demuxer_stream.h"
 #include "media/base/video_decoder.h"
 #include "media/filters/decrypting_demuxer_stream.h"
 
 namespace media {
 
@@ skipping 228 matching lines @@
     return;
   }
 
   const std::string stream_type = DecoderStreamTraits<StreamType>::ToString();
   media_log_->SetBooleanProperty((stream_type + "_dds").c_str(),
                                  decrypting_demuxer_stream_);
   media_log_->SetStringProperty((stream_type + "_decoder").c_str(),
                                 decoder_->GetDisplayName());
 
   if (state_ == STATE_REINITIALIZING_DECODER) {
+    // Fall back succeeded.
+    if (GetStreamType() == DemuxerStream::VIDEO)

[DaleCurtis, 2015/01/13 19:20:50]

Why the get StreamType() method? Does StreamType == not work?

+      UMA_HISTOGRAM_BOOLEAN("Media.VideoDecoderFallback", true);
     CompleteDecoderReinitialization(true);
     return;
   }
 
   // Initialization succeeded.
+  if (GetStreamType() == DemuxerStream::VIDEO)
+    UMA_HISTOGRAM_BOOLEAN("Media.VideoDecoderFallback", false);
   state_ = STATE_NORMAL;
   if (StreamTraits::NeedsBitstreamConversion(decoder_.get()))
     stream_->EnableBitstreamConverter();
   base::ResetAndReturn(&init_cb_).Run(true);
 }
 
 template <DemuxerStream::Type StreamType>
 void DecoderStream<StreamType>::SatisfyRead(
     Status status,
     const scoped_refptr<Output>& output) {
@@ skipping 307 matching lines @@
   }
 
   // The resetting process will be continued in OnDecoderReinitialized().
   ReinitializeDecoder();
 }
 
 template class DecoderStream<DemuxerStream::VIDEO>;
 template class DecoderStream<DemuxerStream::AUDIO>;
 
 }  // namespace media