cc: Introduce BeginFrame sequence numbers and acknowledgements.

cc/trees/layer_tree_host_impl.cc

 // Copyright 2011 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 "cc/trees/layer_tree_host_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 161 matching lines @@
 }
 
 }  // namespace
 
 DEFINE_SCOPED_UMA_HISTOGRAM_TIMER(PendingTreeDurationHistogramTimer,
                                   "Scheduling.%s.PendingTreeDuration");
 
 LayerTreeHostImpl::FrameData::FrameData()
     : render_surface_layer_list(nullptr),
       has_no_damage(false),
-      may_contain_video(false) {}
+      may_contain_video(false),
+      begin_frame_source_id(0),
+      begin_frame_number(0),
+      oldest_incorporated_frame(0) {}
 
 LayerTreeHostImpl::FrameData::~FrameData() {}
 
 std::unique_ptr<LayerTreeHostImpl> LayerTreeHostImpl::Create(
     const LayerTreeSettings& settings,
     LayerTreeHostImplClient* client,
     TaskRunnerProvider* task_runner_provider,
     RenderingStatsInstrumentation* rendering_stats_instrumentation,
     TaskGraphRunner* task_graph_runner,
     std::unique_ptr<MutatorHost> mutator_host,
@@ skipping 1458 matching lines @@
 
   // Collect all resource ids in the render passes into a single array.
   ResourceProvider::ResourceIdArray resources;
   for (const auto& render_pass : frame->render_passes) {
     for (auto* quad : render_pass->quad_list) {
       for (ResourceId resource_id : quad->resources)
         resources.push_back(resource_id);
     }
   }
 
+  metadata.begin_frame_source_id = frame->begin_frame_source_id;
+  metadata.begin_frame_number = frame->begin_frame_number;
+  metadata.oldest_incorporated_frame = frame->oldest_incorporated_frame;
 
   CompositorFrame compositor_frame;
   compositor_frame.metadata = std::move(metadata);
   resource_provider_->PrepareSendToParent(resources,
                                           &compositor_frame.resource_list);
   compositor_frame.render_pass_list = std::move(frame->render_passes);
   compositor_frame_sink_->SubmitCompositorFrame(std::move(compositor_frame));
 
   // The next frame should start by assuming nothing has changed, and changes
   // are noted as they occur.
@@ skipping 2412 matching lines @@
       worker_context_visibility_ =
           worker_context->CacheController()->ClientBecameVisible();
     } else {
       worker_context->CacheController()->ClientBecameNotVisible(
           std::move(worker_context_visibility_));
     }
   }
 }
 
 }  // namespace cc