cc: Plumbing for BeginFrameSource based on Surfaces

cc/surfaces/surface.cc

 // Copyright 2014 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/surfaces/surface.h"
 
 #include <algorithm>
 
 #include "cc/output/compositor_frame.h"
 #include "cc/output/copy_output_request.h"
@@ skipping 17 matching lines @@
   ClearCopyRequests();
   if (current_frame_ && factory_) {
     ReturnedResourceArray current_resources;
     TransferableResource::ReturnResources(
         current_frame_->delegated_frame_data->resource_list,
         &current_resources);
     factory_->UnrefResources(current_resources);
   }
   if (!draw_callback_.is_null())
     draw_callback_.Run(SurfaceDrawStatus::DRAW_SKIPPED);
+
+  if (factory_)
+    factory_->SetBeginFrameSource(surface_id_, NULL);
 }
 
 void Surface::QueueFrame(scoped_ptr<CompositorFrame> frame,
                          const DrawCallback& callback) {
   DCHECK(factory_);
   ClearCopyRequests();
 
   if (frame) {
     TakeLatencyInfo(&frame->metadata.latency_info);
   }
@@ skipping 109 matching lines @@
   destruction_dependencies_.erase(
       std::remove_if(destruction_dependencies_.begin(),
                      destruction_dependencies_.end(),
                      [sequences, valid_id_namespaces](SurfaceSequence seq) {
                        return (!!sequences->erase(seq) ||
                                !valid_id_namespaces->count(seq.id_namespace));
                      }),
       destruction_dependencies_.end());
 }
 
+void Surface::AddBeginFrameSource(BeginFrameSource* begin_frame_source) {
+  DCHECK(base::STLIsSorted(begin_frame_sources_));
+  DCHECK(!ContainsValue(begin_frame_sources_, begin_frame_source));
+  begin_frame_sources_.insert(begin_frame_source);
+  UpdatePrimaryBeginFrameSource();
+}
+
+void Surface::RemoveBeginFrameSource(BeginFrameSource* begin_frame_source) {
+  size_t erase_count = begin_frame_sources_.erase(begin_frame_source);
+  DCHECK_EQ(1u, erase_count);
+  UpdatePrimaryBeginFrameSource();
+}
+
+void Surface::UpdatePrimaryBeginFrameSource() {
+  // Ensure the BeginFrameSources are sorted so our we make a stable decision
+  // regarding which source is primary.
+  // TODO(brianderson): Do something smarter based on coverage instead.
+  DCHECK(base::STLIsSorted(begin_frame_sources_));
+
+  BeginFrameSource* primary_source = nullptr;
+  if (!begin_frame_sources_.empty())
+    primary_source = *begin_frame_sources_.begin();
+
+  if (factory_)
+    factory_->SetBeginFrameSource(surface_id_, primary_source);
+}
+
 void Surface::ClearCopyRequests() {
   if (current_frame_) {
     for (const auto& render_pass :
          current_frame_->delegated_frame_data->render_pass_list) {
       for (const auto& copy_request : render_pass->copy_requests)
         copy_request->SendEmptyResult();
     }
   }
 }
 
 }  // namespace cc