Move capture scheduling logic from VideoScheduler to CaptureScheduler.

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 e2a3f945533aec44f68f2d58c1860f07494e90a5..8c54942bff51167ed4003aaa4fa5a884b4055bcf 100644
--- a/remoting/host/video_scheduler.cc
+++ b/remoting/host/video_scheduler.cc
@@ -14,6 +14,7 @@
 #include "base/stl_util.h"
 #include "base/sys_info.h"
 #include "base/time/time.h"
+#include "remoting/host/capture_scheduler.h"
 #include "remoting/proto/control.pb.h"
 #include "remoting/proto/internal.pb.h"
 #include "remoting/proto/video.pb.h"
@@ -26,10 +27,6 @@
 
 namespace remoting {
 
-// Maximum number of frames that can be processed simultaneously.
-// TODO(hclam): Move this value to CaptureScheduler.
-static const int kMaxPendingFrames = 2;
-
 // Interval between empty keep-alive frames. These frames are sent only when the
 // stream is paused or inactive for some other reason (e.g. when blocked on
 // capturer). To prevent PseudoTCP from resetting congestion window this value
@@ -60,10 +57,6 @@ VideoScheduler::VideoScheduler(
       encoder_(encoder.Pass()),
       cursor_stub_(cursor_stub),
       video_stub_(video_stub),
-      pending_frames_(0),
-      capture_pending_(false),
-      did_skip_frame_(false),
-      is_paused_(false),
       latest_event_timestamp_(0) {
   DCHECK(network_task_runner_->BelongsToCurrentThread());
   DCHECK(capturer_);
@@ -79,74 +72,17 @@ webrtc::SharedMemory* VideoScheduler::CreateSharedMemory(size_t size) {
   return nullptr;
 }
 
-void VideoScheduler::OnCaptureCompleted(webrtc::DesktopFrame* frame) {
-  DCHECK(capture_task_runner_->BelongsToCurrentThread());
-
-  capture_pending_ = false;
-
-  scoped_ptr<webrtc::DesktopFrame> owned_frame(frame);
-
-  if (owned_frame) {
-    scheduler_.RecordCaptureTime(
-        base::TimeDelta::FromMilliseconds(owned_frame->capture_time_ms()));
-  }
-
-  // Even when |frame| is nullptr we still need to post it to the encode thread
-  // to make sure frames are freed in the same order they are received and
-  // that we don't start capturing frame n+2 before frame n is freed.
-  encode_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&VideoScheduler::EncodeFrame, this,
-                            base::Passed(&owned_frame), latest_event_timestamp_,
-                            base::TimeTicks::Now()));
-
-  // If a frame was skipped, try to capture it again.
-  if (did_skip_frame_) {
-    capture_task_runner_->PostTask(
-        FROM_HERE, base::Bind(&VideoScheduler::CaptureNextFrame, this));
-  }
-}
-
-void VideoScheduler::OnMouseCursor(webrtc::MouseCursor* cursor) {
-  DCHECK(capture_task_runner_->BelongsToCurrentThread());
-
-  scoped_ptr<webrtc::MouseCursor> owned_cursor(cursor);
-
-  // Do nothing if the scheduler is being stopped.
-  if (!capturer_)
-    return;
-
-  scoped_ptr<protocol::CursorShapeInfo> cursor_proto(
-      new protocol::CursorShapeInfo());
-  cursor_proto->set_width(cursor->image()->size().width());
-  cursor_proto->set_height(cursor->image()->size().height());
-  cursor_proto->set_hotspot_x(cursor->hotspot().x());
-  cursor_proto->set_hotspot_y(cursor->hotspot().y());
-
-  cursor_proto->set_data(std::string());
-  uint8_t* current_row = cursor->image()->data();
-  for (int y = 0; y < cursor->image()->size().height(); ++y) {
-    cursor_proto->mutable_data()->append(
-        current_row,
-        current_row + cursor->image()->size().width() *
-            webrtc::DesktopFrame::kBytesPerPixel);
-    current_row += cursor->image()->stride();
-  }
-
-  network_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&VideoScheduler::SendCursorShape, this,
-                            base::Passed(&cursor_proto)));
-}
-
-void VideoScheduler::OnMouseCursorPosition(
-    webrtc::MouseCursorMonitor::CursorState state,
-    const webrtc::DesktopVector& position) {
-  // We're not subscribing to mouse position changes.
-  NOTREACHED();
-}
-
 void VideoScheduler::Start() {
   DCHECK(network_task_runner_->BelongsToCurrentThread());
 
+  keep_alive_timer_.reset(new base::DelayTimer<VideoScheduler>(
+      FROM_HERE, base::TimeDelta::FromMilliseconds(kKeepAlivePacketIntervalMs),
+      this, &VideoScheduler::SendKeepAlivePacket));
+
+  capture_scheduler_.reset(new CaptureScheduler(
+      base::Bind(&VideoScheduler::CaptureNextFrame, this)));
+  capture_scheduler_->Start();
+
   capture_task_runner_->PostTask(
       FROM_HERE, base::Bind(&VideoScheduler::StartOnCaptureThread, this));
 }
@@ -172,13 +108,8 @@ void VideoScheduler::Pause(bool pause) {
     return;
   }
 
-  if (is_paused_ != pause) {
-    is_paused_ = pause;
-
-    // Restart captures if we're resuming and there are none scheduled.
-    if (!is_paused_ && capture_timer_ && !capture_timer_->IsRunning())
-      CaptureNextFrame();
-  }
+  if (capture_scheduler_)
+    capture_scheduler_->Pause(pause);
 }
 
 void VideoScheduler::SetLatestEventTimestamp(int64 latest_event_timestamp) {
@@ -228,89 +159,92 @@ VideoScheduler::~VideoScheduler() {
 
 // Capturer thread -------------------------------------------------------------
 
-void VideoScheduler::StartOnCaptureThread() {
+void VideoScheduler::OnCaptureCompleted(webrtc::DesktopFrame* frame) {
   DCHECK(capture_task_runner_->BelongsToCurrentThread());
-  DCHECK(!capture_timer_);
-
-  // Start mouse cursor monitor.
-  mouse_cursor_monitor_->Init(this, webrtc::MouseCursorMonitor::SHAPE_ONLY);
 
-  // Start the capturer.
-  capturer_->Start(this);
-
-  capture_timer_.reset(new base::OneShotTimer<VideoScheduler>());
-  keep_alive_timer_.reset(new base::DelayTimer<VideoScheduler>(
-      FROM_HERE, base::TimeDelta::FromMilliseconds(kKeepAlivePacketIntervalMs),
-      this, &VideoScheduler::SendKeepAlivePacket));
+  // Even when |frame| is nullptr we still need to post it to the encode thread
+  // to make sure frames are freed in the same order they are received and
+  // that we don't start capturing frame n+2 before frame n is freed.
+  encode_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&VideoScheduler::EncodeFrame, this,
+                            base::Passed(make_scoped_ptr(frame)),
+                            latest_event_timestamp_, base::TimeTicks::Now()));
 
-  // Capture first frame immediately.
-  CaptureNextFrame();
+  capture_scheduler_->OnCaptureCompleted();
 }
 
-void VideoScheduler::StopOnCaptureThread() {
+void VideoScheduler::OnMouseCursor(webrtc::MouseCursor* cursor) {
   DCHECK(capture_task_runner_->BelongsToCurrentThread());
 
-  // This doesn't deleted already captured frames, so encoder can keep using the
-  // frames that were captured previously.
-  capturer_.reset();
+  scoped_ptr<webrtc::MouseCursor> owned_cursor(cursor);
 
-  // |capture_timer_| must be destroyed on the thread on which it is used.
-  capture_timer_.reset();
-}
+  scoped_ptr<protocol::CursorShapeInfo> cursor_proto(
+      new protocol::CursorShapeInfo());
+  cursor_proto->set_width(cursor->image()->size().width());
+  cursor_proto->set_height(cursor->image()->size().height());
+  cursor_proto->set_hotspot_x(cursor->hotspot().x());
+  cursor_proto->set_hotspot_y(cursor->hotspot().y());
 
-void VideoScheduler::ScheduleNextCapture() {
-  DCHECK(capture_task_runner_->BelongsToCurrentThread());
+  cursor_proto->set_data(std::string());
+  uint8_t* current_row = cursor->image()->data();
+  for (int y = 0; y < cursor->image()->size().height(); ++y) {
+    cursor_proto->mutable_data()->append(
+        current_row,
+        current_row + cursor->image()->size().width() *
+            webrtc::DesktopFrame::kBytesPerPixel);
+    current_row += cursor->image()->stride();
+  }
 
-  capture_timer_->Start(FROM_HERE,
-                        scheduler_.NextCaptureDelay(),
-                        this,
-                        &VideoScheduler::CaptureNextFrame);
+  network_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&VideoScheduler::SendCursorShape, this,
+                            base::Passed(&cursor_proto)));
 }
 
-void VideoScheduler::CaptureNextFrame() {
-  DCHECK(capture_task_runner_->BelongsToCurrentThread());
+void VideoScheduler::OnMouseCursorPosition(
+    webrtc::MouseCursorMonitor::CursorState state,
+    const webrtc::DesktopVector& position) {
+  // We're not subscribing to mouse position changes.
+  NOTREACHED();
+}
 
-  // If we are stopping (|capturer_| is nullptr), or paused, then don't capture.
-  if (!capturer_ || is_paused_)
-    return;
+void VideoScheduler::StartOnCaptureThread() {
+  DCHECK(capture_task_runner_->BelongsToCurrentThread());
+  DCHECK(!capture_scheduler_);
 
-  // Make sure we have at most two outstanding recordings. We can simply return
-  // if we can't make a capture now, the next capture will be started by the
-  // end of an encode operation.
-  if (pending_frames_ >= kMaxPendingFrames || capture_pending_) {
-    did_skip_frame_ = true;
-    return;
-  }
+  mouse_cursor_monitor_->Init(this, webrtc::MouseCursorMonitor::SHAPE_ONLY);
+  capturer_->Start(this);
+}
 
-  did_skip_frame_ = false;
+void VideoScheduler::StopOnCaptureThread() {
+  DCHECK(capture_task_runner_->BelongsToCurrentThread());
 
-  // At this point we are going to perform one capture so save the current time.
-  pending_frames_++;
-  DCHECK_LE(pending_frames_, kMaxPendingFrames);
+  // This doesn't deleted already captured frames, so encoder can keep using the
+  // frames that were captured previously.
+  capturer_.reset();
 
-  // Before doing a capture schedule for the next one.
-  ScheduleNextCapture();
+  mouse_cursor_monitor_.reset();
+  capture_scheduler_.reset();
+}
 
-  capture_pending_ = true;
+void VideoScheduler::CaptureNextFrame() {
+  DCHECK(capture_task_runner_->BelongsToCurrentThread());
 
-  // Capture the mouse shape.
+  // Capture mouse shape first and then screen content.
   mouse_cursor_monitor_->Capture();
-
-  // And finally perform one capture.
   capturer_->Capture(webrtc::DesktopRegion());
 }
 
-void VideoScheduler::FrameCaptureCompleted() {
+void VideoScheduler::ProcessFrameEncodedOnCaptureThread(
+    base::TimeDelta encode_time) {
   DCHECK(capture_task_runner_->BelongsToCurrentThread());
 
-  // Decrement the pending capture count.
-  pending_frames_--;
-  DCHECK_GE(pending_frames_, 0);
+  capture_scheduler_->OnFrameEncoded(encode_time);
+}
+
+void VideoScheduler::ProcessFrameSentOnCaptureThread() {
+  DCHECK(capture_task_runner_->BelongsToCurrentThread());
 
-  // If we've skipped a frame capture because too we had too many captures
-  // pending then schedule one now.
-  if (did_skip_frame_)
-    CaptureNextFrame();
+  capture_scheduler_->OnFrameSent();
 }
 
 // Network thread --------------------------------------------------------------
@@ -334,7 +268,8 @@ void VideoScheduler::OnVideoPacketSent() {
   keep_alive_timer_->Reset();
 
   capture_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&VideoScheduler::FrameCaptureCompleted, this));
+      FROM_HERE,
+      base::Bind(&VideoScheduler::ProcessFrameSentOnCaptureThread, this));
 }
 
 void VideoScheduler::SendKeepAlivePacket() {
@@ -397,8 +332,10 @@ void VideoScheduler::EncodeFrame(
   // old frame to be freed by then.
   frame.reset();
 
-  scheduler_.RecordEncodeTime(
-      base::TimeDelta::FromMilliseconds(packet->encode_time_ms()));
+  capture_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&VideoScheduler::ProcessFrameEncodedOnCaptureThread, this,
+                 base::TimeDelta::FromMilliseconds(packet->encode_time_ms())));
   network_task_runner_->PostTask(
       FROM_HERE, base::Bind(&VideoScheduler::SendVideoPacket, this,
                             base::Passed(&packet)));