pepper: VideoEncoder: use same constraints as media::VideoFrame for software encoder

content/renderer/pepper/video_encoder_shim.cc

Index: content/renderer/pepper/video_encoder_shim.cc
diff --git a/content/renderer/pepper/video_encoder_shim.cc b/content/renderer/pepper/video_encoder_shim.cc
index 8866fae0f623b05017506ced298afe0fe013736e..c3735deb964f498e1f401cb7c8817a26558a600a 100644
--- a/content/renderer/pepper/video_encoder_shim.cc
+++ b/content/renderer/pepper/video_encoder_shim.cc
@@ -101,9 +101,12 @@ void VideoEncoderShim::EncoderImpl::Initialize(
 
   encoder_->UpdateRates(initial_bitrate);
 
+  gfx::Size coded_size =
+      media::VideoFrame::PlaneSize(input_format, 0, input_visible_size);
+
   media_task_runner_->PostTask(
       FROM_HERE, base::Bind(&VideoEncoderShim::OnRequireBitstreamBuffers, shim_,
-                            kInputFrameCount, input_visible_size,
+                            kInputFrameCount, coded_size,
                             kBitstreamBufferSize));
 }