Make check for 'opened' consistent across all audio stream implementations of Start() and log an ...

media/audio/mac/audio_low_latency_output_mac.cc

 // Copyright (c) 2011 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/audio/mac/audio_low_latency_output_mac.h"
 
 #include <CoreServices/CoreServices.h>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
@@ skipping 157 matching lines @@
   if (output_unit_)
     CloseComponent(output_unit_);
 
   // Inform the audio manager that we have been closed. This can cause our
   // destruction.
   manager_->ReleaseOutputStream(this);
 }
 
 void AUAudioOutputStream::Start(AudioSourceCallback* callback) {
   DCHECK(callback);
+  DLOG_IF(ERROR, !output_unit_) << "Open() has not been called successfully";
+  if (!output_unit_)
+    return;
+
   source_ = callback;
 
   AudioOutputUnitStart(output_unit_);
 }
 
 void AUAudioOutputStream::Stop() {
   // We request a synchronous stop, so the next call can take some time. In
   // the windows implementation we block here as well.
   source_ = NULL;
 
@@ skipping 174 matching lines @@
   // Get the delay between the moment getting the callback and the scheduled
   // time stamp that tells when the data is going to be played out.
   UInt64 output_time_ns = AudioConvertHostTimeToNanos(
       output_time_stamp->mHostTime);
   UInt64 now_ns = AudioConvertHostTimeToNanos(AudioGetCurrentHostTime());
   double delay_frames = static_cast<double>
       (1e-9 * (output_time_ns - now_ns) * format_.mSampleRate);
 
   return (delay_frames + hardware_latency_frames_);
 }