Separate client surface reference tracking from FrameGenerator.

cc/surfaces/embedded_surface_tracker.cc

Index: cc/surfaces/embedded_surface_tracker.cc
diff --git a/cc/surfaces/embedded_surface_tracker.cc b/cc/surfaces/embedded_surface_tracker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..45413824c803c074a0e5b8234985f448b193a296
--- /dev/null
+++ b/cc/surfaces/embedded_surface_tracker.cc
@@ -0,0 +1,95 @@
+// 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 "cc/surfaces/embedded_surface_tracker.h"
+
+#include <utility>
+
+#include "base/logging.h"
+
+namespace cc {
+
+EmbeddedSurfaceTracker::EmbeddedSurfaceTracker() {}
+
+EmbeddedSurfaceTracker::~EmbeddedSurfaceTracker() {}
+
+void EmbeddedSurfaceTracker::SetCurrentSurfaceId(const SurfaceId& surface_id) {
+  DCHECK(surface_id.is_valid());
+  DCHECK_NE(current_surface_id_, surface_id);
+
+  // The last submitted CompositorFrame for |current_surface_id_| still embeds
+  // the surfaces in |references_to_remove_| and hasn't embedded the surfaces in
+  // |references_to_add_| yet.
+  references_to_remove_.clear();
+  references_to_add_.clear();
+
+  current_surface_id_ = surface_id;
+
+  // Add references from updated |current_surface_id_| to all embedded surfaces.
+  for (auto& map_entry : embedded_surfaces_)
+    AddReference(current_surface_id_, map_entry.second);
+}
+
+bool EmbeddedSurfaceTracker::EmbedSurface(const SurfaceId& embedded_id) {
+  auto iter = embedded_surfaces_.find(embedded_id.frame_sink_id());
+
+  // This is the first surface for the FrameSinkId.
+  if (iter == embedded_surfaces_.end()) {
+    if (HasValidSurfaceId())
+      AddReference(current_surface_id_, embedded_id);
+
+    // Add record that surface is embedded.
+    embedded_surfaces_[embedded_id.frame_sink_id()] = embedded_id;
+    return true;
+  }
+
+  // This is not the first surface for the FrameSinkId, we are unembedding the
+  // old surface and embedding the new surface.
+  SurfaceId& stored_surface_id = iter->second;
+  DCHECK_NE(stored_surface_id, embedded_id);
+
+  if (HasValidSurfaceId()) {
+    RemoveReference(current_surface_id_, stored_surface_id);
+    AddReference(current_surface_id_, embedded_id);
+  }
+
+  stored_surface_id = embedded_id;
+  return false;
+}
+
+void EmbeddedSurfaceTracker::UnembedSurface(const FrameSinkId& frame_sink_id) {
+  auto iter = embedded_surfaces_.find(frame_sink_id);
+  if (iter == embedded_surfaces_.end())
+    return;
+
+  if (HasValidSurfaceId())
+    RemoveReference(current_surface_id_, iter->second);
+
+  // Remove record that surface is embedded.
+  embedded_surfaces_.erase(iter);
+}
+
+std::vector<SurfaceReference> EmbeddedSurfaceTracker::GetReferencesToAdd() {
+  std::vector<SurfaceReference> references;
+  std::swap(references, references_to_add_);
+  return references;
+}
+
+std::vector<SurfaceReference> EmbeddedSurfaceTracker::GetReferencesToRemove() {
+  std::vector<SurfaceReference> references;
+  std::swap(references, references_to_remove_);
+  return references;
+}
+
+void EmbeddedSurfaceTracker::AddReference(const SurfaceId& parent_id,
+                                          const SurfaceId& child_id) {
+  references_to_add_.push_back(SurfaceReference(parent_id, child_id));
+}
+
+void EmbeddedSurfaceTracker::RemoveReference(const SurfaceId& parent_id,
+                                             const SurfaceId& child_id) {
+  references_to_remove_.push_back(SurfaceReference(parent_id, child_id));
+}
+
+}  // namespace cc