Allow layers to signal that additional sequences are needed before surface destruction

cc/layers/surface_layer.h

Index: cc/layers/surface_layer.h
diff --git a/cc/layers/surface_layer.h b/cc/layers/surface_layer.h
index 0b886ebe2c98c780f70db2b1cbd2ce3aac426e1e..6dd55b1f94a9a9451c22c7ac97037a7409058488 100644
--- a/cc/layers/surface_layer.h
+++ b/cc/layers/surface_layer.h
@@ -8,29 +8,48 @@
 #include "cc/base/cc_export.h"
 #include "cc/layers/layer.h"
 #include "cc/surfaces/surface_id.h"
+#include "cc/surfaces/surface_sequence.h"
 
 namespace cc {
+class SatisfySwapPromise;
 
 // A layer that renders a surface referencing the output of another compositor
 // instance or client.
 class CC_EXPORT SurfaceLayer : public Layer {
  public:
-  static scoped_refptr<SurfaceLayer> Create();
+  // This callback is run when a SurfaceSequence needs to be satisfied, but
+  // the parent compositor is unable to. It can be called on either the main
+  // or impl threads.
+  using SatisfyCallback = base::Callback<void(SurfaceSequence)>;
+
+  // This callback is run to require that a specific SurfaceSequence is
+  // received before a SurfaceId is destroyed.
+  using RequireCallback = base::Callback<void(SurfaceId, SurfaceSequence)>;
+
+  static scoped_refptr<SurfaceLayer> Create(SatisfyCallback satisfy_callback,
+                                            RequireCallback require_callback);
 
   void SetSurfaceId(SurfaceId surface_id);
 
   // Layer overrides.
   scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl) override;
+  void SetLayerTreeHost(LayerTreeHost* host) override;
   void PushPropertiesTo(LayerImpl* layer) override;
 
  protected:
-  SurfaceLayer();
+  SurfaceLayer(SatisfyCallback satisfy_callback,
+               RequireCallback require_callback);
   bool HasDrawableContent() const override;
 
  private:
   ~SurfaceLayer() override;
+  void CreateNewDestroySequence();
+  void SatisfyDestroySequence();
 
   SurfaceId surface_id_;
+  SurfaceSequence destroy_sequence_;
+  SatisfyCallback satisfy_callback_;
+  RequireCallback require_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(SurfaceLayer);
 };