Simplify VideoEncoder interface.

remoting/host/video_scheduler.cc

Index: remoting/host/video_scheduler.cc
diff --git a/remoting/host/video_scheduler.cc b/remoting/host/video_scheduler.cc
index 883166b39ce5c4b1c8ad7c18775d2c302262a50a..3b2973314d7a4c613649a2a8c8fda91f8837b034 100644
--- a/remoting/host/video_scheduler.cc
+++ b/remoting/host/video_scheduler.cc
@@ -295,19 +295,14 @@ void VideoScheduler::EncodeFrame(
     return;
   }
 
-  encoder_->Encode(
-      frame.get(), base::Bind(&VideoScheduler::EncodedDataAvailableCallback,
-                              this, sequence_number));
-  capture_task_runner_->DeleteSoon(FROM_HERE, frame.release());
-}
-
-void VideoScheduler::EncodedDataAvailableCallback(
-    int64 sequence_number,
-    scoped_ptr<VideoPacket> packet) {
-  DCHECK(encode_task_runner_->BelongsToCurrentThread());
-
+  scoped_ptr<VideoPacket> packet = encoder_->Encode(*frame);
   packet->set_client_sequence_number(sequence_number);
 
+  // Destroy the frame before sending |packet| because SendVideoPacket() may
+  // trigger another frame to be captured, and the screen capturer expects the
+  // old frame to be freed by then.
+  frame.reset();
+
   bool last = (packet->flags() & VideoPacket::LAST_PACKET) != 0;
   if (last) {
     scheduler_.RecordEncodeTime(