Change exo::SurfaceFactoryOwner to exo::ExoCompositorFrameSink

components/exo/compositor_frame_sink_holder.cc

Index: components/exo/compositor_frame_sink_holder.cc
diff --git a/components/exo/compositor_frame_sink_holder.cc b/components/exo/compositor_frame_sink_holder.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d303bee83664e2cac4c7b848d9c739c744196c69
--- /dev/null
+++ b/components/exo/compositor_frame_sink_holder.cc
@@ -0,0 +1,132 @@
+// 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 "components/exo/compositor_frame_sink_holder.h"
+
+#include "cc/resources/returned_resource.h"
+#include "components/exo/surface.h"
+
+namespace exo {
+
+////////////////////////////////////////////////////////////////////////////////
+// CompositorFrameSinkHolder, public:
+
+CompositorFrameSinkHolder::CompositorFrameSinkHolder(
+    cc::mojom::MojoCompositorFrameSinkPtr compositor_frame_sink,
+    Surface* surface,
+    cc::mojom::MojoCompositorFrameSinkClientRequest request)
+    : compositor_frame_sink_(std::move(compositor_frame_sink)),
+      surface_(surface),
+      begin_frame_source_(base::MakeUnique<cc::ExternalBeginFrameSource>(this)),
+      binding_(this, std::move(request)),
+      weak_factory_(this) {
+  surface_->AddSurfaceObserver(this);
+}
+
+bool CompositorFrameSinkHolder::HasReleaseCallbacksForResource(
+    cc::ResourceId id) {
+  return release_callbacks_.find(id) != release_callbacks_.end();
+}
+
+void CompositorFrameSinkHolder::AddResourceReleaseCallback(
+    cc::ResourceId id,
+    std::unique_ptr<cc::SingleReleaseCallback> callback) {
+  release_callbacks_[id] = std::make_pair(this, std::move(callback));
+}
+
+void CompositorFrameSinkHolder::ActivateFrameCallbacks(
+    std::list<FrameCallback>* frame_callbacks) {
+  active_frame_callbacks_.splice(active_frame_callbacks_.end(),
+                                 *frame_callbacks);
+  UpdateNeedsBeginFrame();
+}
+
+void CompositorFrameSinkHolder::CancelFrameCallbacks() {
+  // Call pending frame callbacks with a null frame time to indicate that they
+  // have been cancelled.
+  for (const auto& frame_callback : active_frame_callbacks_)
+    frame_callback.Run(base::TimeTicks());
+}
+
+void CompositorFrameSinkHolder::SetNeedsBeginFrame(bool needs_begin_frame) {
+  needs_begin_frame_ = needs_begin_frame;
+  OnNeedsBeginFrames(needs_begin_frame);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// cc::mojom::MojoCompositorFrameSinkClient overrides:
+
+void CompositorFrameSinkHolder::DidReceiveCompositorFrameAck() {
+  // TODO(staraz): Implement this
+}
+
+void CompositorFrameSinkHolder::OnBeginFrame(const cc::BeginFrameArgs& args) {
+  while (!active_frame_callbacks_.empty()) {
+    active_frame_callbacks_.front().Run(args.frame_time);
+    active_frame_callbacks_.pop_front();
+  }
+  begin_frame_source_->OnBeginFrame(args);
+}
+
+void CompositorFrameSinkHolder::ReclaimResources(
+    const cc::ReturnedResourceArray& resources) {
+  scoped_refptr<CompositorFrameSinkHolder> holder(this);

[reveman, 2016/12/07 22:13:37]

I haven't seen this pattern used elsewhere in chromium. Can you instead just
make sure we don't access any member variables after running the callbacks and
add a comment that makes it clear that running the callbacks has to be the last
thing the functions does as they might result in the instance being destroyed?

[Alex Z., 2016/12/09 16:16:27]

Done.

[reveman, 2016/12/09 16:33:59]

I'm still seeing release_callbacks_ accessed below the callback. Is that not a
problem anymore? Can you also explain how these callbacks can result in the
instance being destroyed? Its surprising that someone can call this and have a
reference to the object but then it's destroyed before the function call
returns.

[Alex Z., 2016/12/09 19:47:11]

I am moving the release callback to a local variable before erasing it from the
map.

+  for (auto& resource : resources) {
+    auto it = release_callbacks_.find(resource.id);
+    DCHECK(it != release_callbacks_.end());
+    it->second.second->Run(resource.sync_token, resource.lost);
+    release_callbacks_.erase(it);
+  }
+}
+
+void CompositorFrameSinkHolder::WillDrawSurface() {
+  if (surface_)
+    surface_->WillDraw();
+
+  UpdateNeedsBeginFrame();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// cc::BeginFrameObserver overrides:
+
+const cc::BeginFrameArgs& CompositorFrameSinkHolder::LastUsedBeginFrameArgs()
+    const {
+  return last_begin_frame_args_;
+}
+
+void CompositorFrameSinkHolder::OnBeginFrameSourcePausedChanged(bool paused) {}
+
+////////////////////////////////////////////////////////////////////////////////
+// cc::ExternalBeginFrameSouceClient overrides:
+
+void CompositorFrameSinkHolder::OnNeedsBeginFrames(bool needs_begin_frames) {
+  compositor_frame_sink_->SetNeedsBeginFrame(needs_begin_frames);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// SurfaceObserver overrides:
+
+void CompositorFrameSinkHolder::OnSurfaceDestroying(Surface* surface) {
+  surface_->RemoveSurfaceObserver(this);
+  surface_ = nullptr;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ExoComopositorFrameSink, private:
+
+CompositorFrameSinkHolder::~CompositorFrameSinkHolder() {}
+
+void CompositorFrameSinkHolder::UpdateNeedsBeginFrame() {
+  if (!begin_frame_source_)
+    return;
+
+  bool needs_begin_frame = !active_frame_callbacks_.empty();
+  if (needs_begin_frame == needs_begin_frame_)
+    return;
+
+  needs_begin_frame_ = needs_begin_frame;
+  OnNeedsBeginFrames(needs_begin_frame_);
+}
+
+}  // namespace exo