cc::SurfaceDependencyTracker should not crash when a Display goes away

components/viz/frame_sinks/mojo_frame_sink_manager.cc

 // Copyright 2015 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/viz/frame_sinks/mojo_frame_sink_manager.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "cc/base/switches.h"
 #include "cc/scheduler/begin_frame_source.h"
 #include "cc/surfaces/display.h"
 #include "cc/surfaces/surface_dependency_tracker.h"
 #include "components/viz/frame_sinks/display_provider.h"
 #include "components/viz/frame_sinks/gpu_compositor_frame_sink.h"
 #include "components/viz/frame_sinks/gpu_root_compositor_frame_sink.h"
 
 namespace viz {
 
 MojoFrameSinkManager::MojoFrameSinkManager(bool use_surface_references,
                                            DisplayProvider* display_provider)
     : manager_(use_surface_references
                    ? cc::SurfaceManager::LifetimeType::REFERENCES
                    : cc::SurfaceManager::LifetimeType::SEQUENCES),
       display_provider_(display_provider),
       binding_(this) {
   manager_.AddObserver(this);
+  dependency_tracker_ = base::MakeUnique<cc::SurfaceDependencyTracker>(
+      &manager_, manager_.GetPrimaryBeginFrameSource());
+  manager_.SetDependencyTracker(dependency_tracker_.get());
 }
 
 MojoFrameSinkManager::~MojoFrameSinkManager() {
   DCHECK(thread_checker_.CalledOnValidThread());
+  manager_.SetDependencyTracker(nullptr);
+  dependency_tracker_.reset();
   manager_.RemoveObserver(this);
 }
 
 void MojoFrameSinkManager::Connect(
     cc::mojom::FrameSinkManagerRequest request,
     cc::mojom::FrameSinkManagerClientPtr client) {
   DCHECK(!binding_.is_bound());
   binding_.Bind(std::move(request));
   client_ = std::move(client);
 }
 
 void MojoFrameSinkManager::CreateRootCompositorFrameSink(
     const cc::FrameSinkId& frame_sink_id,
     gpu::SurfaceHandle surface_handle,
     cc::mojom::MojoCompositorFrameSinkAssociatedRequest request,
     cc::mojom::MojoCompositorFrameSinkPrivateRequest private_request,
     cc::mojom::MojoCompositorFrameSinkClientPtr client,
     cc::mojom::DisplayPrivateAssociatedRequest display_private_request) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK_NE(surface_handle, gpu::kNullSurfaceHandle);
   DCHECK_EQ(0u, compositor_frame_sinks_.count(frame_sink_id));
   DCHECK(display_provider_);
 
   std::unique_ptr<cc::BeginFrameSource> begin_frame_source;
   std::unique_ptr<cc::Display> display = display_provider_->CreateDisplay(
       frame_sink_id, surface_handle, &begin_frame_source);
 
-  // Lazily inject a SurfaceDependencyTracker into SurfaceManager if surface
-  // synchronization is enabled.
-  if (!manager_.dependency_tracker() &&
-      base::CommandLine::ForCurrentProcess()->HasSwitch(
-          cc::switches::kEnableSurfaceSynchronization)) {
-    std::unique_ptr<cc::SurfaceDependencyTracker> dependency_tracker(
-        new cc::SurfaceDependencyTracker(&manager_, begin_frame_source.get()));
-    manager_.SetDependencyTracker(std::move(dependency_tracker));
-  }
-
   compositor_frame_sinks_[frame_sink_id] =
       base::MakeUnique<GpuRootCompositorFrameSink>(
           this, &manager_, frame_sink_id, std::move(display),
           std::move(begin_frame_source), std::move(request),
           std::move(private_request), std::move(client),
           std::move(display_private_request));
 }
 
 void MojoFrameSinkManager::CreateCompositorFrameSink(
     const cc::FrameSinkId& frame_sink_id,
@@ skipping 65 matching lines @@
 
 void MojoFrameSinkManager::OnPrivateConnectionLost(
     const cc::FrameSinkId& frame_sink_id,
     bool destroy_compositor_frame_sink) {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (destroy_compositor_frame_sink)
     DestroyCompositorFrameSink(frame_sink_id);
 }
 
 }  // namespace viz