Fix media_log() crash in fuzzer tests.

media/formats/mpeg/adts_stream_parser.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/formats/mpeg/adts_stream_parser.h"
 
 #include <stddef.h>
 
 #include "build/build_config.h"
 #include "media/base/media_log.h"
@@ skipping 56 matching lines @@
            << " version 0x" << version
            << " layer 0x" << layer
            << " profile 0x" << profile
            << " sample_rate_index 0x" << sample_rate_index
            << " channel_layout_index 0x" << channel_layout_index;
 
   const int bytes_read = reader.bits_read() / 8;
   if (sync != 0xfff || layer != 0 || frame_length < bytes_read ||
       sample_rate_index >= kADTSFrequencyTableSize ||
       channel_layout_index >= kADTSChannelLayoutTableSize) {
-    MEDIA_LOG(DEBUG, media_log())
-        << "Invalid header data :" << std::hex << " sync 0x" << sync
-        << " version 0x" << version << " layer 0x" << layer
-        << " sample_rate_index 0x" << sample_rate_index
-        << " channel_layout_index 0x" << channel_layout_index;
+    if (media_log()) {
+      MEDIA_LOG(DEBUG, media_log())
+          << "Invalid header data :" << std::hex << " sync 0x" << sync
+          << " version 0x" << version << " layer 0x" << layer
+          << " sample_rate_index 0x" << sample_rate_index
+          << " channel_layout_index 0x" << channel_layout_index;
+    }
     return -1;
   }
 
   if (sample_rate)
     *sample_rate = kADTSFrequencyTable[sample_rate_index];
 
   if (frame_size)
     *frame_size = frame_length;
 
   if (sample_count)
@@ skipping 19 matching lines @@
     extra_data->push_back(esds >> 8);
     extra_data->push_back(esds & 0xFF);
     if (media_log())
       DCHECK(mp4::AAC().Parse(*extra_data, media_log()));
   }
 
   return bytes_read;
 }
 
 }  // namespace media