Convert offscreen canvas to use FrameSinkManagerHost.

content/browser/renderer_host/offscreen_canvas_surface_impl.cc

 // 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 "content/browser/renderer_host/offscreen_canvas_surface_impl.h"
 
 #include <utility>
 
 #include "base/bind_helpers.h"
 #include "base/memory/ptr_util.h"
-#include "cc/surfaces/surface.h"
 #include "cc/surfaces/surface_manager.h"
+#include "content/browser/compositor/frame_sink_manager_host.h"
 #include "content/browser/compositor/surface_utils.h"
 #include "content/browser/renderer_host/offscreen_canvas_compositor_frame_sink_manager.h"
-#include "content/public/browser/browser_thread.h"
 
 namespace content {
 
 OffscreenCanvasSurfaceImpl::OffscreenCanvasSurfaceImpl(
     const cc::FrameSinkId& parent_frame_sink_id,
     const cc::FrameSinkId& frame_sink_id,
     cc::mojom::FrameSinkManagerClientPtr client)
     : client_(std::move(client)),
       frame_sink_id_(frame_sink_id),
       parent_frame_sink_id_(parent_frame_sink_id) {
   OffscreenCanvasCompositorFrameSinkManager::GetInstance()
       ->RegisterOffscreenCanvasSurfaceInstance(frame_sink_id_, this);
 }
 
 OffscreenCanvasSurfaceImpl::~OffscreenCanvasSurfaceImpl() {
-  if (frame_sink_id_.is_valid()) {
-    OffscreenCanvasCompositorFrameSinkManager::GetInstance()
-        ->UnregisterOffscreenCanvasSurfaceInstance(frame_sink_id_);
+  if (has_registered_frame_sink_hierarchy_) {
+    GetFrameSinkManagerHost()->UnregisterFrameSinkHierarchy(
+        parent_frame_sink_id_, frame_sink_id_);
   }
+  OffscreenCanvasCompositorFrameSinkManager::GetInstance()
+      ->UnregisterOffscreenCanvasSurfaceInstance(frame_sink_id_);
 }
 
 // static
 void OffscreenCanvasSurfaceImpl::Create(
     const cc::FrameSinkId& parent_frame_sink_id,
     const cc::FrameSinkId& frame_sink_id,
     cc::mojom::FrameSinkManagerClientPtr client,
     blink::mojom::OffscreenCanvasSurfaceRequest request) {
   std::unique_ptr<OffscreenCanvasSurfaceImpl> impl =
       base::MakeUnique<OffscreenCanvasSurfaceImpl>(
           parent_frame_sink_id, frame_sink_id, std::move(client));
   OffscreenCanvasSurfaceImpl* surface_service = impl.get();
   surface_service->binding_ =
       mojo::MakeStrongBinding(std::move(impl), std::move(request));
 }
 
+void OffscreenCanvasSurfaceImpl::CreateCompositorFrameSink(
+    cc::mojom::MojoCompositorFrameSinkClientPtr client,
+    cc::mojom::MojoCompositorFrameSinkRequest request) {
+  DCHECK(!compositor_frame_sink_private_.is_bound());

[piman, 2017/04/12 18:08:43]

What makes this DCHECK valid? Can't the (untrusted) renderer call
CreateCompositorFrameSink twice?

[kylechar, 2017/04/12 18:48:35]

It wouldn't be valid to call this twice, but I don't think it would be an issue
if a malicious renderer did it. The malicious renderer would just replace the
MojoCompositorFrameSink connection it owns with a new identical connection. It
could also reopen a connection that it chose to close.

However, maybe it's better to strictly enforce CreateCompositorFrameSink only
ever gets called once? Done.

+
+  GetFrameSinkManagerHost()->CreateCompositorFrameSink(
+      frame_sink_id_, std::move(request),
+      mojo::MakeRequest(&compositor_frame_sink_private_), std::move(client));
+
+  GetFrameSinkManagerHost()->RegisterFrameSinkHierarchy(parent_frame_sink_id_,
+                                                        frame_sink_id_);
+  has_registered_frame_sink_hierarchy_ = true;
+}
+
 void OffscreenCanvasSurfaceImpl::OnSurfaceCreated(
     const cc::SurfaceInfo& surface_info) {
   DCHECK_EQ(surface_info.id().frame_sink_id(), frame_sink_id_);
   if (!current_local_surface_id_.is_valid() ||
       surface_info.id().local_surface_id() != current_local_surface_id_) {
     current_local_surface_id_ = surface_info.id().local_surface_id();
     if (client_)
       client_->OnSurfaceCreated(surface_info);
   }
 }
 
 void OffscreenCanvasSurfaceImpl::Require(const cc::SurfaceId& surface_id,
                                          const cc::SurfaceSequence& sequence) {
   GetSurfaceManager()->RequireSequence(surface_id, sequence);
 }
 
 void OffscreenCanvasSurfaceImpl::Satisfy(const cc::SurfaceSequence& sequence) {
   GetSurfaceManager()->SatisfySequence(sequence);
 }
 
 }  // namespace content