V4L2VDA: fix starting the device poll thread twice.

media/gpu/v4l2_video_decode_accelerator.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/gpu/v4l2_video_decode_accelerator.h"
 
 #include <dlfcn.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/videodev2.h>
@@ skipping 1754 matching lines @@
 void V4L2VideoDecodeAccelerator::ResetDoneTask() {
   DVLOGF(3);
   DCHECK(decoder_thread_.task_runner()->BelongsToCurrentThread());
   TRACE_EVENT0("Video Decoder", "V4L2VDA::ResetDoneTask");
 
   if (decoder_state_ == kError) {
     DVLOGF(2) << "early out: kError state";
     return;
   }
 
-  if (!StartDevicePoll())
-    return;
+  // Start poll thread if NotifyFlushDoneIfNeeded has not already.
+  if (!device_poll_thread_.IsRunning()) {
+    if (!StartDevicePoll())
+      return;
+  }
 
   // Reset format-specific bits.
   if (video_profile_ >= H264PROFILE_MIN && video_profile_ <= H264PROFILE_MAX) {
     decoder_h264_parser_.reset(new H264Parser());
   }
 
   // Jobs drained, we're finished resetting.
   DCHECK_EQ(decoder_state_, kResetting);
   decoder_state_ = kInitialized;
 
@@ skipping 837 matching lines @@
       StartResolutionChange();
   }
 }
 
 void V4L2VideoDecodeAccelerator::ImageProcessorError() {
   LOGF(ERROR) << "Image processor error";
   NOTIFY_ERROR(PLATFORM_FAILURE);
 }
 
 }  // namespace media