Ensure DiscardPadding is parsed as a signed integer.

media/filters/opus_audio_decoder.cc

 // 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.
 
 #include "media/filters/opus_audio_decoder.h"
 
 #include <cmath>
 
 #include "base/single_thread_task_runner.h"
 #include "base/sys_byteorder.h"
@@ skipping 504 matching lines @@
     }
     if (input->discard_padding().InMicroseconds() > 0) {
       int discard_padding = TimeDeltaToAudioFrames(
           input->discard_padding(), config_.samples_per_second());
       if (discard_padding < 0 || discard_padding > frames_to_output) {
         DVLOG(1) << "Invalid file. Incorrect discard padding value.";
         return false;
       }
       output_buffer->get()->TrimEnd(discard_padding);
       frames_to_output -= discard_padding;
+    } else {
+      DCHECK_EQ(input->discard_padding().InMicroseconds(), 0);
     }
   } else {
     frames_to_discard_ -= frames_to_output;
     frames_to_output = 0;
   }
 
+  // Discard the buffer to indicate we need more data.
+  if (!frames_to_output) {
+    *output_buffer = NULL;
+    return true;
+  }
+
   // Assign timestamp and duration to the buffer.
   output_buffer->get()->set_timestamp(output_timestamp_helper_->GetTimestamp());
   output_buffer->get()->set_duration(
       output_timestamp_helper_->GetFrameDuration(frames_to_output));
-  output_timestamp_helper_->AddFrames(frames_decoded);
-
-  // Discard the buffer to indicate we need more data.
-  if (!frames_to_output)
-    *output_buffer = NULL;
-
+  output_timestamp_helper_->AddFrames(frames_to_output);
   return true;
 }
 
 }  // namespace media