Make ash::VideoDetector recover from viz crashes

Observe mojo connection errors and re-establish the connection once
it's lost.

Bug: 780514
Change-Id: Ic393f737bee97b97ed588ea47040327a4b639a4b
Reviewed-on: https://chromium-review.googlesource.com/c/1340945Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Saman Sami <samans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609009}

ash/shell.cc

@@ -1175,12 +1175,7 @@ void Shell::Init(
         std::make_unique<DockedMagnifierController>();
   }
 
-  viz::mojom::VideoDetectorObserverPtr observer;
-  video_detector_ =
-      std::make_unique<VideoDetector>(mojo::MakeRequest(&observer));
-  aura_env_->context_factory_private()
-      ->GetHostFrameSinkManager()
-      ->AddVideoDetectorObserver(std::move(observer));
+  video_detector_ = std::make_unique<VideoDetector>();
 
   tooltip_controller_.reset(new views::corewm::TooltipController(
       std::unique_ptr<views::corewm::Tooltip>(new views::corewm::TooltipAura)));

ash/system/power/video_activity_notifier_unittest.cc

@@ -23,8 +23,7 @@ class VideoActivityNotifierTest : public AshTestBase {
     AshTestBase::SetUp();
     power_client_ = static_cast<chromeos::FakePowerManagerClient*>(
         chromeos::DBusThreadManager::Get()->GetPowerManagerClient());
-    detector_ = std::make_unique<VideoDetector>(
-        viz::mojom::VideoDetectorObserverRequest());
+    detector_ = std::make_unique<VideoDetector>();
     notifier_.reset(new VideoActivityNotifier(detector_.get()));
   }
 

ash/wm/video_detector.cc

@@ -7,6 +7,7 @@
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/shell.h"
 #include "ash/wm/window_state.h"
+#include "components/viz/host/host_frame_sink_manager.h"
 #include "ui/aura/env.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
@@ -15,15 +16,25 @@
 
 namespace ash {
 
-VideoDetector::VideoDetector(viz::mojom::VideoDetectorObserverRequest request)
+namespace {
+
+// How long to wait before attempting to re-establish a lost connection.
+constexpr base::TimeDelta kReEstablishConnectionDelay =
+    base::TimeDelta::FromMilliseconds(100);
+
+}  // namespace
+
+VideoDetector::VideoDetector()
     : state_(State::NOT_PLAYING),
       video_is_playing_(false),
       window_observer_manager_(this),
       scoped_session_observer_(this),
       is_shutting_down_(false),
-      binding_(this, std::move(request)) {
+      binding_(this),
+      weak_factory_(this) {
   Shell::Get()->aura_env()->AddObserver(this);
   Shell::Get()->AddShellObserver(this);
+  EstablishConnectionToViz();
 }
 
 VideoDetector::~VideoDetector() {
@@ -101,4 +112,28 @@ void VideoDetector::OnVideoActivityEnded() {
   UpdateState();
 }
 
+void VideoDetector::EstablishConnectionToViz() {
+  viz::mojom::VideoDetectorObserverPtr observer;
+  if (binding_.is_bound())
+    binding_.Close();
+  binding_.Bind(mojo::MakeRequest(&observer));
+  binding_.set_connection_error_handler(base::BindOnce(
+      &VideoDetector::OnConnectionError, base::Unretained(this)));
+  Shell::Get()
+      ->aura_env()
+      ->context_factory_private()
+      ->GetHostFrameSinkManager()
+      ->AddVideoDetectorObserver(std::move(observer));
+}
+
+void VideoDetector::OnConnectionError() {
+  if (video_is_playing_)
+    OnVideoActivityEnded();
+  base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+      FROM_HERE,
+      base::BindOnce(&VideoDetector::EstablishConnectionToViz,
+                     weak_factory_.GetWeakPtr()),
+      kReEstablishConnectionDelay);
+}
+
 }  // namespace ash

ash/wm/video_detector.h

@@ -59,7 +59,7 @@ class ASH_EXPORT VideoDetector : public aura::EnvObserver,
     virtual ~Observer() {}
   };
 
-  VideoDetector(viz::mojom::VideoDetectorObserverRequest request);
+  VideoDetector();
   ~VideoDetector() override;
 
   State state() const { return state_; }
@@ -89,6 +89,13 @@ class ASH_EXPORT VideoDetector : public aura::EnvObserver,
   // Updates |state_| and notifies |observers_| if it changed.
   void UpdateState();
 
+  // Connects to Viz and starts observing video activities.
+  void EstablishConnectionToViz();
+
+  // Called when connection to Viz is lost. The connection will be
+  // re-established after a short delay.
+  void OnConnectionError();
+
   // Current playback state.
   State state_;
 
@@ -107,6 +114,8 @@ class ASH_EXPORT VideoDetector : public aura::EnvObserver,
 
   mojo::Binding<viz::mojom::VideoDetectorObserver> binding_;
 
+  base::WeakPtrFactory<VideoDetector> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(VideoDetector);
 };