Move surface reference code to CompositorFrameSinkSupport.

cc/surfaces/compositor_frame_sink_support.cc

Index: cc/surfaces/compositor_frame_sink_support.cc
diff --git a/cc/surfaces/compositor_frame_sink_support.cc b/cc/surfaces/compositor_frame_sink_support.cc
index 95222ed1defc2354e69faf20ac12300a4b439b61..e7848f8021f16e3d3cadc78723a0076d505d2e9f 100644
--- a/cc/surfaces/compositor_frame_sink_support.cc
+++ b/cc/surfaces/compositor_frame_sink_support.cc
@@ -4,12 +4,17 @@
 
 #include "cc/surfaces/compositor_frame_sink_support.h"
 
+#include <algorithm>
+#include <utility>
+#include <vector>
+
 #include "cc/output/compositor_frame.h"
 #include "cc/scheduler/begin_frame_source.h"
 #include "cc/surfaces/compositor_frame_sink_support_client.h"
 #include "cc/surfaces/display.h"
 #include "cc/surfaces/surface.h"
 #include "cc/surfaces/surface_manager.h"
+#include "cc/surfaces/surface_reference.h"
 
 namespace cc {
 
@@ -25,6 +30,7 @@ CompositorFrameSinkSupport::CompositorFrameSinkSupport(
       display_begin_frame_source_(std::move(display_begin_frame_source)),
       display_(std::move(display)),
       surface_factory_(frame_sink_id_, surface_manager_, this),
+      reference_tracker_(frame_sink_id),
       weak_factory_(this) {
   surface_manager_->RegisterFrameSinkId(frame_sink_id_);
   surface_manager_->RegisterSurfaceFactoryClient(frame_sink_id_, this);
@@ -36,6 +42,12 @@ CompositorFrameSinkSupport::CompositorFrameSinkSupport(
 }
 
 CompositorFrameSinkSupport::~CompositorFrameSinkSupport() {
+  // For display root surfaces, the surface is no longer going to be visible
+  // so make it unreachable from the top-level root.
+  if (surface_manager_->using_surface_references() && display_ &&
+      reference_tracker_.current_surface_id().is_valid())
+    RemoveTopLevelRootReference(reference_tracker_.current_surface_id());
+
   for (auto& child_frame_sink_id : child_frame_sinks_) {
     DCHECK(child_frame_sink_id.is_valid());
     surface_manager_->UnregisterFrameSinkHierarchy(frame_sink_id_,
@@ -62,14 +74,31 @@ void CompositorFrameSinkSupport::SubmitCompositorFrame(
     const LocalSurfaceId& local_surface_id,
     CompositorFrame frame) {
   ++ack_pending_count_;
-  surface_factory_.SubmitCompositorFrame(
-      local_surface_id, std::move(frame),
-      base::Bind(&CompositorFrameSinkSupport::DidReceiveCompositorFrameAck,
-                 weak_factory_.GetWeakPtr()));
-  if (display_) {
-    display_->SetLocalSurfaceId(local_surface_id,
-                                frame.metadata.device_scale_factor);
+  float device_scale_factor = frame.metadata.device_scale_factor;
+
+  if (surface_manager_->using_surface_references()) {
+    SurfaceId last_surface_id = reference_tracker_.current_surface_id();
+
+    // Populate list of surface references to add and remove based on reference
+    // surfaces in current frame compared with the last frame.
+    reference_tracker_.UpdateReferences(local_surface_id,
+                                        frame.metadata.referenced_surfaces);
+
+    surface_factory_.SubmitCompositorFrame(
+        local_surface_id, std::move(frame),
+        base::Bind(&CompositorFrameSinkSupport::DidReceiveCompositorFrameAck,
+                   weak_factory_.GetWeakPtr()));
+
+    UpdateSurfaceReferences(last_surface_id, local_surface_id);
+  } else {
+    surface_factory_.SubmitCompositorFrame(
+        local_surface_id, std::move(frame),
+        base::Bind(&CompositorFrameSinkSupport::DidReceiveCompositorFrameAck,
+                   weak_factory_.GetWeakPtr()));
   }
+
+  if (display_)
+    display_->SetLocalSurfaceId(local_surface_id, device_scale_factor);
 }
 
 void CompositorFrameSinkSupport::Require(const LocalSurfaceId& local_surface_id,
@@ -82,6 +111,51 @@ void CompositorFrameSinkSupport::Satisfy(const SurfaceSequence& sequence) {
   surface_manager_->SatisfySequence(sequence);
 }
 
+void CompositorFrameSinkSupport::UpdateSurfaceReferences(
+    const SurfaceId& last_surface_id,
+    const LocalSurfaceId& local_surface_id) {
+  const bool surface_id_changed =
+      last_surface_id.local_surface_id() != local_surface_id;
+
+  // If this is a display root surface and the SurfaceId is changing, make the
+  // new SurfaceId reachable from the top-level root.
+  if (display_ && surface_id_changed)
+    AddTopLevelRootReference(reference_tracker_.current_surface_id());
+
+  // Add references based on CompositorFrame referenced surfaces. If the
+  // SurfaceId has changed all referenced surfaces will be in this list.
+  if (!reference_tracker_.references_to_add().empty()) {
+    surface_manager_->AddSurfaceReferences(
+        reference_tracker_.references_to_add());
+  }
+
+  // If this is a display root surface and the SurfaceId is changing, make the
+  // old SurfaceId unreachable from the top-level root. This needs to happen
+  // after adding all references for the new SurfaceId.
+  if (display_ && surface_id_changed && last_surface_id.is_valid())
+    RemoveTopLevelRootReference(last_surface_id);
+
+  // Remove references based on CompositorFrame referenced surfaces. If the
+  // SurfaceId has changed this list will be empty.
+  if (!reference_tracker_.references_to_remove().empty()) {
+    DCHECK(!surface_id_changed);
+    surface_manager_->RemoveSurfaceReferences(
+        reference_tracker_.references_to_remove());
+  }
+}
+
+void CompositorFrameSinkSupport::AddTopLevelRootReference(
+    const SurfaceId& surface_id) {
+  SurfaceReference reference(surface_manager_->GetRootSurfaceId(), surface_id);
+  surface_manager_->AddSurfaceReferences({reference});
+}
+
+void CompositorFrameSinkSupport::RemoveTopLevelRootReference(
+    const SurfaceId& surface_id) {
+  SurfaceReference reference(surface_manager_->GetRootSurfaceId(), surface_id);
+  surface_manager_->RemoveSurfaceReferences({reference});
+}
+
 void CompositorFrameSinkSupport::DidReceiveCompositorFrameAck() {
   DCHECK_GT(ack_pending_count_, 0);
   ack_pending_count_--;