Add check for renderer client id.

content/browser/renderer_host/offscreen_canvas_provider_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_provider_impl.h"
 
 #include "content/browser/compositor/surface_utils.h"
 #include "content/browser/renderer_host/offscreen_canvas_compositor_frame_sink_manager.h"
 #include "content/browser/renderer_host/offscreen_canvas_surface_impl.h"
 
 namespace content {
 
-OffscreenCanvasProviderImpl::OffscreenCanvasProviderImpl() = default;
+OffscreenCanvasProviderImpl::OffscreenCanvasProviderImpl(
+    uint32_t renderer_client_id)
+    : renderer_client_id_(renderer_client_id) {}
 
 OffscreenCanvasProviderImpl::~OffscreenCanvasProviderImpl() = default;
 
 void OffscreenCanvasProviderImpl::Add(
     blink::mojom::OffscreenCanvasProviderRequest request) {
   bindings_.AddBinding(this, std::move(request));
 }
 
 void OffscreenCanvasProviderImpl::CreateOffscreenCanvasSurface(
     const cc::FrameSinkId& parent_frame_sink_id,
     const cc::FrameSinkId& frame_sink_id,
     cc::mojom::FrameSinkManagerClientPtr client,
     blink::mojom::OffscreenCanvasSurfaceRequest request) {
+  // TODO(kylechar): Kill the renderer instead of crashing chrome.
+  CHECK_EQ(parent_frame_sink_id.client_id(), renderer_client_id_);
+  CHECK_EQ(frame_sink_id.client_id(), renderer_client_id_);

[piman, 2017/04/12 22:53:37]

Can we just return early / do nothing (and DLOG etc.)?
It will mess up the renderer, but it's the one asking for trouble :)

[kylechar, 2017/04/13 17:09:18]

Done.

+
   OffscreenCanvasSurfaceImpl::Create(parent_frame_sink_id, frame_sink_id,
                                      std::move(client), std::move(request));
 }
 
 void OffscreenCanvasProviderImpl::CreateCompositorFrameSink(
     const cc::FrameSinkId& frame_sink_id,
     cc::mojom::MojoCompositorFrameSinkClientPtr client,
     cc::mojom::MojoCompositorFrameSinkRequest request) {
+  // TODO(kylechar): Kill the renderer instead of crashing chrome.
+  CHECK_EQ(frame_sink_id.client_id(), renderer_client_id_);

[piman, 2017/04/12 22:53:37]

ditto.

[kylechar, 2017/04/13 17:09:18]

Done.

+
   // TODO(kylechar): Add test for bad |frame_sink_id|.
   auto* manager = OffscreenCanvasCompositorFrameSinkManager::GetInstance();
   auto* surface_impl = manager->GetSurfaceInstance(frame_sink_id);
   if (!surface_impl) {
     DLOG(ERROR) << "No OffscreenCanvasSurfaceImpl for " << frame_sink_id;
     return;
   }
 
   surface_impl->CreateCompositorFrameSink(std::move(client),
                                           std::move(request));
 }
 
 }  // namespace content