Fix deadlock

Emmanuel Garcia · Emmanuel Garcia · commit a57f0792a04d · 2022-01-27T16:15:21.000-08:00
diff --git a/shell/common/rasterizer.cc b/shell/common/rasterizer.cc
@@ -81,6 +81,12 @@ void Rasterizer::Setup(std::unique_ptr<Surface> surface) {
   }
 }
 
+void Rasterizer::TeardownExternalViewEmbedder() {
+  if (external_view_embedder_) {
+    external_view_embedder_->Teardown();
+  }
+}
+
 void Rasterizer::Teardown() {
   auto context_switch =
       surface_ ? surface_->MakeRenderContextCurrent() : nullptr;
@@ -97,10 +103,6 @@ void Rasterizer::Teardown() {
     raster_thread_merger_->UnMergeNowIfLastOne();
     raster_thread_merger_->SetMergeUnmergeCallback(nullptr);
   }
-
-  if (external_view_embedder_) {
-    external_view_embedder_->Teardown();
-  }
 }
 
 void Rasterizer::EnableThreadMergerIfNeeded() {
diff --git a/shell/common/rasterizer.h b/shell/common/rasterizer.h
@@ -140,6 +140,13 @@ class Rasterizer final : public SnapshotDelegate {
   ///
   void Teardown();
 
+  //----------------------------------------------------------------------------
+  /// @brief      Releases any resource used by the external view embedder.
+  ///             For example, overlay surfaces or Android views.
+  ///             On Android, this method post a task to the platform thread,
+  ///             and waits until it completes.
+  void TeardownExternalViewEmbedder();
+
   //----------------------------------------------------------------------------
   /// @brief      Notifies the rasterizer that there is a low memory situation
   ///             and it must purge as many unnecessary resources as possible.
diff --git a/shell/common/shell.cc b/shell/common/shell.cc
@@ -885,6 +885,11 @@ void Shell::OnPlatformViewDestroyed() {
   fml::TaskRunner::RunNowOrPostTask(task_runners_.GetRasterTaskRunner(),
                                     raster_task);
   latch.Wait();
+  // On Android, the external view embedder posts a task to the platform thread,
+  // and waits until it completes.
+  // As a result, the platform thread must not be blocked prior to calling
+  // this method.
+  rasterizer_->TeardownExternalViewEmbedder();
 }
 
 // |PlatformView::Delegate|
diff --git a/shell/platform/android/platform_view_android.cc b/shell/platform/android/platform_view_android.cc
@@ -254,8 +254,7 @@ std::unique_ptr<Surface> PlatformViewAndroid::CreateRenderingSurface() {
 std::shared_ptr<ExternalViewEmbedder>
 PlatformViewAndroid::CreateExternalViewEmbedder() {
   return std::make_shared<AndroidExternalViewEmbedder>(
-      *android_context_, jni_facade_, surface_factory_,
-      std::move(task_runners_));
+      *android_context_, jni_facade_, surface_factory_, task_runners_);
 }
 
 // |PlatformView|

Original file line number	Diff line number	Diff line change
`@@ -81,6 +81,12 @@ void Rasterizer::Setup(std::unique_ptr<Surface> surface) {`
`81`	`81`	`}`
`82`	`82`	`}`
`83`	`83`
	`84`	`+void Rasterizer::TeardownExternalViewEmbedder() {`
	`85`	`+ if (external_view_embedder_) {`
	`86`	`+ external_view_embedder_->Teardown();`
	`87`	`+ }`
	`88`	`+}`
	`89`	`+`
`84`	`90`	`void Rasterizer::Teardown() {`
`85`	`91`	`auto context_switch =`
`86`	`92`	`surface_ ? surface_->MakeRenderContextCurrent() : nullptr;`
`@@ -97,10 +103,6 @@ void Rasterizer::Teardown() {`
`97`	`103`	`raster_thread_merger_->UnMergeNowIfLastOne();`
`98`	`104`	`raster_thread_merger_->SetMergeUnmergeCallback(nullptr);`
`99`	`105`	`}`
`100`		`-`
`101`		`- if (external_view_embedder_) {`
`102`		`- external_view_embedder_->Teardown();`
`103`		`- }`
`104`	`106`	`}`
`105`	`107`
`106`	`108`	`void Rasterizer::EnableThreadMergerIfNeeded() {`
Original file line number	Diff line number	Diff line change
`@@ -254,8 +254,7 @@ std::unique_ptr<Surface> PlatformViewAndroid::CreateRenderingSurface() {`
`254`	`254`	`std::shared_ptr<ExternalViewEmbedder>`
`255`	`255`	`PlatformViewAndroid::CreateExternalViewEmbedder() {`
`256`	`256`	`return std::make_shared<AndroidExternalViewEmbedder>(`
`257`		`- *android_context_, jni_facade_, surface_factory_,`
`258`		`- std::move(task_runners_));`
	`257`	`+ *android_context_, jni_facade_, surface_factory_, task_runners_);`
`259`	`258`	`}`
`260`	`259`
`261`	`260`	`// \|PlatformView\|`