Use MojoCompositorFrameSink in RendererCompositorFrameSink

content/browser/frame_sink_provider_impl.cc

+// Copyright 2017 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/frame_sink_provider_impl.h"
+#include "content/browser/renderer_host/render_widget_host_impl.h"
+
+namespace content {
+
+FrameSinkProviderImpl::FrameSinkProviderImpl(int32_t process_id)
+    : process_id_(process_id), binding_(this) {}
+
+FrameSinkProviderImpl::~FrameSinkProviderImpl() = default;
+
+void FrameSinkProviderImpl::Bind(mojom::FrameSinkProviderRequest request) {
+  if (binding_.is_bound())

[Ken Rockot(use gerrit already), 2017/04/10 23:31:11]

Some surprising and unexpected behavior could result from code which
accidentally ends up binding the same provider twice. Maybe this could DCHECK
instead? And then you could add an explicit Unbind which you call from
RPHI::ProcessDied?

[Saman Sami, 2017/04/11 00:09:52]

Is it appropriate to add a dcheck when a malicious renderer can trigger it?
Maybe I should just print an error and reject the request?

+    binding_.Close();
+  binding_.Bind(std::move(request));
+}
+
+void FrameSinkProviderImpl::CreateForWidget(
+    int32_t widget_id,
+    cc::mojom::MojoCompositorFrameSinkRequest request,
+    cc::mojom::MojoCompositorFrameSinkClientPtr client) {
+  RenderWidgetHostImpl* render_widget_host_impl =
+      RenderWidgetHostImpl::FromID(process_id_, widget_id);
+  if (!render_widget_host_impl) {
+    DLOG(ERROR) << "No RenderWidgetHost exists with id " << widget_id
+                << "in process " << process_id_;
+    return;
+  }
+  render_widget_host_impl->RequestMojoCompositorFrameSink(std::move(request),
+                                                          std::move(client));
+}
+
+}  // namespace content