Fix DCHECKs in V4l2VideoDevice.

content/common/gpu/media/v4l2_image_processor.cc

Index: content/common/gpu/media/v4l2_image_processor.cc
diff --git a/content/common/gpu/media/v4l2_image_processor.cc b/content/common/gpu/media/v4l2_image_processor.cc
index 1a9dd292180e0c92a421f0e9df3417beaab7d41a..f988e9042126382bdfe7d8e9acae4c3f45755100 100644
--- a/content/common/gpu/media/v4l2_image_processor.cc
+++ b/content/common/gpu/media/v4l2_image_processor.cc
@@ -214,6 +214,7 @@ void V4L2ImageProcessor::DestroyTask() {
 }
 
 bool V4L2ImageProcessor::CreateInputBuffers() {
+  DVLOG(3) << __func__;
   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
   DCHECK(!input_streamon_);
 
@@ -284,6 +285,7 @@ bool V4L2ImageProcessor::CreateInputBuffers() {
 }
 
 bool V4L2ImageProcessor::CreateOutputBuffers() {
+  DVLOG(3) << __func__;
   DCHECK(child_message_loop_proxy_->BelongsToCurrentThread());
   DCHECK(!output_streamon_);