Change exo::SurfaceFactoryOwner to exo::ExoCompositorFrameSink

components/exo/exo_compositor_frame_sink.h

Index: components/exo/exo_compositor_frame_sink.h
diff --git a/components/exo/exo_compositor_frame_sink.h b/components/exo/exo_compositor_frame_sink.h
new file mode 100644
index 0000000000000000000000000000000000000000..a263de4702e90781fc3ae2138c8fca73cee3c84c
--- /dev/null
+++ b/components/exo/exo_compositor_frame_sink.h
@@ -0,0 +1,94 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.

[reveman, 2016/11/16 03:48:38]

Why does this need to be in a new file when it's only used by exo::Surface? If
it contains enough logic to justify a new file then I think it should also be
unit tested by adding a compositor_frame_sink_unittest.cc file.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <list>
+#include <memory>
+#include <set>
+#include <utility>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
+#include "cc/ipc/compositor_frame.mojom.h"
+#include "cc/ipc/mojo_compositor_frame_sink.mojom.h"
+#include "cc/resources/transferable_resource.h"
+#include "cc/scheduler/begin_frame_source.h"
+#include "cc/surfaces/surface_factory.h"
+#include "cc/surfaces/surface_factory_client.h"
+#include "cc/surfaces/surface_id_allocator.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "third_party/skia/include/core/SkRegion.h"
+#include "third_party/skia/include/core/SkXfermode.h"
+#include "ui/aura/window.h"
+#include "ui/aura/window_observer.h"
+#include "ui/gfx/geometry/rect.h"
+
+namespace cc {
+class SurfaceFactory;
+}
+
+namespace exo {
+
+// This class owns the SurfaceFactory and keeps track of references to the
+// contents of Buffers. It's keeped alive by references from
+// release_callbacks_. It's destroyed when its owning Surface is destroyed and
+// the last outstanding release callback is called.
+class ExoCompositorFrameSink : public base::RefCounted<ExoCompositorFrameSink>,

[reveman, 2016/11/16 03:48:38]

Exo is typically not used as a prefix inside the exo:: namespace. Can this be
CompositorFrameSink or SurfaceCompositorFrameSink?

+                               public cc::SurfaceFactoryClient,
+                               public cc::BeginFrameObserver {
+ public:
+  ExoCompositorFrameSink(const cc::FrameSinkId& frame_sink_id,
+                         cc::SurfaceManager* surface_manager);
+
+  // cc::SurfaceFactoryClient:
+  void ReturnResources(const cc::ReturnedResourceArray& resources) override;
+  void WillDrawSurface(const cc::LocalFrameId& id,
+                       const gfx::Rect& damage_rect) override;
+  void SetBeginFrameSource(cc::BeginFrameSource* begin_frame_source) override;
+
+  // To be cc::mojom::MojoCompositorFrameSink:
+  void SubmitCompositorFrame(cc::CompositorFrame frame);
+
+  // cc::BeginFrameObserver:
+  void OnBeginFrame(const cc::BeginFrameArgs& args) override;
+  const cc::BeginFrameArgs& LastUsedBeginFrameArgs() const override;
+  void OnBeginFrameSourcePausedChanged(bool paused) override;
+
+  const cc::FrameSinkId& frame_sink_id() { return frame_sink_id_; }

[Fady Samuel, 2016/11/15 23:19:46]

nit: do you need this?

[Alex Z., 2016/11/16 14:55:46]

Done.

+  cc::SurfaceManager* surface_manager() { return surface_manager_; }

[Fady Samuel, 2016/11/15 23:19:46]

nit: do you need this?

[Alex Z., 2016/11/16 14:55:46]

Yes. In CommitSurfaceHierarchy(), the SurfaceManager is needed for
window_->layer()->SetShowSurface()
(https://cs.chromium.org/chromium/src/components/exo/surface.cc?sq=package:chr...)

+
+ private:
+  friend class base::RefCounted<ExoCompositorFrameSink>;
+  friend class Surface;
+
+  ~ExoCompositorFrameSink() override;
+  void UpdateNeedsBeginFrameInternal();
+  void DidRecieveCompositorFrameAck();
+
+  std::map<int,
+           std::pair<scoped_refptr<ExoCompositorFrameSink>,
+                     std::unique_ptr<cc::SingleReleaseCallback>>>
+      release_callbacks_;

[Fady Samuel, 2016/11/15 23:19:46]

What is this for?

[Alex Z., 2016/11/16 14:55:46]

I don't fully understand this part, but it seems the release_callbacks_ contains
the callbacks needed to release resources.
It is updated in exo::Surface::UpdateResource().
The callbacks keep ExoCompositorFrameSink alive.
Inside ExoCompositorFrameSink::ReturnResources(), all callbacks are called and
erased.
Maybe I could move it into exo::Surface?

+  cc::FrameSinkId frame_sink_id_;

[Fady Samuel, 2016/11/15 23:19:46]

Mark as const.

[Alex Z., 2016/11/23 14:25:03]

Done.

+  cc::LocalFrameId local_frame_id_;
+  cc::SurfaceIdAllocator id_allocator_;
+
+  cc::SurfaceManager* surface_manager_;
+  cc::SurfaceFactory surface_factory_;
+
+  int ack_pending_count_ = 0;
+
+  cc::BeginFrameSource* begin_frame_source_ = nullptr;
+
+  gfx::Size last_submitted_frame_size_;
+
+  cc::BeginFrameArgs last_begin_frame_args_;
+
+  bool needs_begin_frame_ = false;
+  bool added_frame_observer_ = false;
+};
+
+}  // namespace exo