Convert offscreen canvas to use FrameSinkManagerHost.

content/browser/renderer_host/offscreen_canvas_surface_impl.cc

Index: content/browser/renderer_host/offscreen_canvas_surface_impl.cc
diff --git a/content/browser/renderer_host/offscreen_canvas_surface_impl.cc b/content/browser/renderer_host/offscreen_canvas_surface_impl.cc
index dd9218cd957eee93aae3f197cf1bd647e61b3e28..7119fd7b67d1d6b5e4d37d4fa5b13483bc85b0b8 100644
--- a/content/browser/renderer_host/offscreen_canvas_surface_impl.cc
+++ b/content/browser/renderer_host/offscreen_canvas_surface_impl.cc
@@ -8,11 +8,10 @@
 
 #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 {
 
@@ -28,10 +27,12 @@ OffscreenCanvasSurfaceImpl::OffscreenCanvasSurfaceImpl(
 }
 
 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
@@ -48,6 +49,20 @@ void OffscreenCanvasSurfaceImpl::Create(
       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_);