Introducing SurfaceReferenceFactory

cc/surfaces/surface_ref.h

Index: cc/surfaces/surface_ref.h
diff --git a/cc/surfaces/surface_ref.h b/cc/surfaces/surface_ref.h
new file mode 100644
index 0000000000000000000000000000000000000000..7ff120292ca78e9fd2d1ff21b8bbe574e691f1ba
--- /dev/null
+++ b/cc/surfaces/surface_ref.h
@@ -0,0 +1,45 @@
+// Copyright (c) 2012 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.
+
+#ifndef CC_SURFACES_SURFACE_REF_H_
+#define CC_SURFACES_SURFACE_REF_H_
+
+#include "cc/output/compositor_frame_metadata.h"
+#include "cc/surfaces/surface_ref_base.h"
+#include "cc/surfaces/surface_sequence.h"
+#include "cc/surfaces/surface_sequence_generator.h"
+#include "cc/trees/layer_tree_host.h"
+
+namespace cc {
+
+template <class T>
+class SurfaceRefWithSequence : public SurfaceRefBase<T> {
+ protected:
+  void BlockImpl() override {

[Fady Samuel, 2016/11/30 19:51:29]

Why is this called block?

+    DCHECK(this->host());
+    seq_ = this->host()->GetSurfaceSequenceGenerator()->CreateSurfaceSequence();
+    DCHECK(seq_.is_valid());
+    RequireSequence(seq_);
+  }
+
+  void AllowImpl() override {

[Fady Samuel, 2016/11/30 19:51:29]

Why is this called allow?

+    DCHECK(seq_.is_valid());
+    SatisfySequence(seq_);
+  }
+
+  virtual void RequireSequence(const SurfaceSequence&) = 0;
+  virtual void SatisfySequence(const SurfaceSequence&) = 0;
+
+  void DelegateLockImpl(CompositorFrameMetadata* metadata) override {

[Fady Samuel, 2016/11/30 19:51:29]

Why is this called DelegateLockImpl? I don't understand what this is supposed to
do.

+    DCHECK(seq_.is_valid());
+    metadata->satisfies_sequences.push_back(seq_.sequence);
+  }
+
+ private:
+  SurfaceSequence seq_;
+};
+
+}  // namespace cc
+
+#endif  // CC_SURFACES_SURFACE_REF_H_