Display Compositor: Allocate LocalFrameId in client.

services/ui/ws/frame_generator.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "services/ui/ws/frame_generator.h"
 
 #include "base/containers/adapters.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/quads/render_pass.h"
 #include "cc/quads/render_pass_draw_quad.h"
@@ skipping 82 matching lines @@
 }
 
 void FrameGenerator::DidReceiveCompositorFrameAck() {}
 
 void FrameGenerator::OnBeginFrame(const cc::BeginFrameArgs& begin_frame_arags) {
   if (!root_window_->visible())
     return;
 
   // 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
     // is still embedded in the last frame.
     // TODO(kylechar): This should be synchronized with SubmitCompositorFrame().
     RemoveDeadSurfaceReferences();
   }
 }
 
 void FrameGenerator::ReclaimResources(
@@ skipping 230 matching lines @@
   cc::SurfaceId underlay_surface_id =
       window->compositor_frame_sink_manager()->GetLatestSurfaceId(
           mojom::CompositorFrameSinkType::UNDERLAY);
   if (underlay_surface_id.is_valid())
     RemoveFrameSinkReference(underlay_surface_id.frame_sink_id());
 }
 
 }  // namespace ws
 
 }  // namespace ui