Avoid unsafe usage of CancelIo() within Windows SyncSocket.

content/browser/renderer_host/media/audio_sync_reader.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 "content/browser/renderer_host/media/audio_sync_reader.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/memory/shared_memory.h"
@@ skipping 126 matching lines @@
   //
   // The counter values may temporarily become out of sync if the renderer is
   // unable to deliver audio fast enough.  It's assumed that the renderer will
   // catch up at some point, which means discarding counter values read from the
   // SyncSocket which don't match our current buffer index.
   size_t bytes_received = 0;
   uint32 renderer_buffer_index = 0;
   while (timeout.InMicroseconds() > 0) {
     bytes_received = socket_->ReceiveWithTimeout(
         &renderer_buffer_index, sizeof(renderer_buffer_index), timeout);
-    if (!bytes_received)
+    if (bytes_received != sizeof(renderer_buffer_index)) {
+      bytes_received = 0;
       break;
+    }
 
-    DCHECK_EQ(bytes_received, sizeof(renderer_buffer_index));
     if (renderer_buffer_index == buffer_index_)
       break;
 
     // Reduce the timeout value as receives succeed, but aren't the right index.
     timeout = finish_time - base::TimeTicks::Now();
   }
 
   // Receive timed out or another error occurred.  Receive can timeout if the
   // renderer is unable to deliver audio data within the allotted time.
   if (!bytes_received || renderer_buffer_index != buffer_index_) {
     DVLOG(2) << "AudioSyncReader::WaitUntilDataIsReady() timed out.";
 
     base::TimeDelta time_since_start = base::TimeTicks::Now() - start_time;
     UMA_HISTOGRAM_CUSTOM_TIMES("Media.AudioOutputControllerDataNotReady",
                                time_since_start,
                                base::TimeDelta::FromMilliseconds(1),
                                base::TimeDelta::FromMilliseconds(1000),
                                50);
     return false;
   }
 
   return true;
 }
 
 }  // namespace content