cc: Force commit on the frame after a copy request

content/browser/compositor/delegated_frame_host.cc

Index: content/browser/compositor/delegated_frame_host.cc
diff --git a/content/browser/compositor/delegated_frame_host.cc b/content/browser/compositor/delegated_frame_host.cc
index 2650a769a64747ad24708362e4ebd647ad9a26a8..39643295ffe688c211e0d9f04210b7a44f23d0eb 100644
--- a/content/browser/compositor/delegated_frame_host.cc
+++ b/content/browser/compositor/delegated_frame_host.cc
@@ -70,6 +70,7 @@ DelegatedFrameHost::DelegatedFrameHost(DelegatedFrameHostClient* client)
       last_output_surface_id_(0),
       pending_delegated_ack_count_(0),
       skipped_frames_(false),
+      force_commit_for_next_frame_(false),
       current_scale_factor_(1.f),
       can_lock_compositor_(YES_CAN_LOCK),
       delegated_frame_evictor_(new DelegatedFrameEvictor(this)) {
@@ -349,6 +350,11 @@ void DelegatedFrameHost::SwapDelegatedFrame(
   gfx::Rect damage_rect_in_dip =
       gfx::ConvertRectToDIP(frame_device_scale_factor, damage_rect);
 
+  if (compositor_ && force_commit_for_next_frame_) {
+    force_commit_for_next_frame_ = false;
+    compositor_->ScheduleDraw();
+  }
+
   if (ShouldSkipFrame(frame_size_in_dip)) {
     cc::CompositorFrameAck ack;
     cc::TransferableResource::ReturnResources(frame_data->resource_list,
@@ -469,6 +475,7 @@ void DelegatedFrameHost::SwapDelegatedFrame(
   }
   released_front_lock_ = NULL;
   current_frame_size_in_dip_ = frame_size_in_dip;
+
   CheckResizeLock();
 
   if (!damage_rect_in_dip.IsEmpty())
@@ -1033,6 +1040,8 @@ void DelegatedFrameHost::RequestCopyOfOutput(
     request_copy_of_output_callback_for_testing_.Run(request.Pass());
   else
     client_->DelegatedFrameHostGetLayer()->RequestCopyOfOutput(request.Pass());
+
+  force_commit_for_next_frame_ = true;

[miu, 2015/12/02 20:32:57]

Idea: Should you also call compositor_->ScheduleDraw() here too?  This might
solve a problem I was mentioning in our meeting, where the compositor can decide
to skip a frame.  It's always kept our "smoothness" performance for tab capture
from being perfect.

[ccameron, 2015/12/02 23:03:22]

That would seem like a separate bug if we're not getting a commit when we
request a copy of the output -- the source of my problem is that that causes a
commit which changes the tree, but there is subsequent commit to un-do that
change. So I'd prefer to keep that to separate changes.

[miu, 2015/12/03 00:23:41]

Acknowledged.

 }
 
 void DelegatedFrameHost::UnlockResources() {