Display Compositor: Allocate LocalFrameId in client.

services/ui/ws/frame_generator.cc

Index: services/ui/ws/frame_generator.cc
diff --git a/services/ui/ws/frame_generator.cc b/services/ui/ws/frame_generator.cc
index f90062be04d38fce4794a366af3d4f0b9e0cd164..0cb87c480e9f796f57eac51952d04701a2ff3e6d 100644
--- a/services/ui/ws/frame_generator.cc
+++ b/services/ui/ws/frame_generator.cc
@@ -100,8 +100,16 @@ void FrameGenerator::OnBeginFrame(const cc::BeginFrameArgs& begin_frame_arags) {
 
   // TODO(fsamuel): We should add a trace for generating a top level frame.
   cc::CompositorFrame frame(GenerateCompositorFrame(root_window_->bounds()));
+
   if (compositor_frame_sink_) {
-    compositor_frame_sink_->SubmitCompositorFrame(std::move(frame));
+    gfx::Size frame_size = last_submitted_frame_size_;
+    if (!frame.render_pass_list.empty())
+      frame_size = frame.render_pass_list[0]->output_rect.size();
+    if (!local_frame_id_.is_valid() || frame_size != last_submitted_frame_size_)
+      local_frame_id_ = id_allocator_.GenerateId();
+    compositor_frame_sink_->SubmitCompositorFrame(local_frame_id_,
+                                                  std::move(frame));
+    last_submitted_frame_size_ = frame_size;
 
     // Remove dead references after we submit a frame. This has to happen after
     // the frame is submitted otherwise we could end up deleting a surface that