Detach the resource context before shutting down the IO thread

shell/common/platform_view.cc

@@ -73,6 +73,8 @@ sk_sp<GrContext> PlatformView::CreateResourceContext() const {
   return nullptr;
 }
 
+void PlatformView::ReleaseResourceContext() const {}
+
 fml::WeakPtr<PlatformView> PlatformView::GetWeakPtr() const {
   return weak_factory_.GetWeakPtr();
 }

shell/common/platform_view.h

@@ -88,6 +88,10 @@ class PlatformView {
   // non-platform task runner.
   virtual sk_sp<GrContext> CreateResourceContext() const;
 
+  // Unlike all other methods on the platform view, this one may be called on a
+  // non-platform task runner.
+  virtual void ReleaseResourceContext() const;
+
   fml::WeakPtr<PlatformView> GetWeakPtr() const;
 
   virtual void UpdateSemantics(blink::SemanticsNodeUpdates updates,

shell/common/shell.cc

@@ -314,11 +314,15 @@ Shell::~Shell() {
 
   fml::TaskRunner::RunNowOrPostTask(
       task_runners_.GetIOTaskRunner(),
-      fml::MakeCopyable(
-          [io_manager = std::move(io_manager_), &io_latch]() mutable {
-            io_manager.reset();
-            io_latch.Signal();
-          }));
+      fml::MakeCopyable([io_manager = std::move(io_manager_),
+                         platform_view = platform_view_.get(),
+                         &io_latch]() mutable {
+        io_manager.reset();
+        if (platform_view) {
+          platform_view->ReleaseResourceContext();
+        }
+        io_latch.Signal();
+      }));
 
   io_latch.Wait();
 

shell/platform/android/android_surface.h

@@ -33,6 +33,8 @@ class AndroidSurface {
 
   virtual bool ResourceContextMakeCurrent() = 0;
 
+  virtual bool ResourceContextClearCurrent() = 0;
+
   virtual bool SetNativeWindow(fml::RefPtr<AndroidNativeWindow> window) = 0;
 };
 

shell/platform/android/android_surface_gl.cc

@@ -82,6 +82,11 @@ bool AndroidSurfaceGL::ResourceContextMakeCurrent() {
   return offscreen_context_->MakeCurrent();
 }
 
+bool AndroidSurfaceGL::ResourceContextClearCurrent() {
+  FML_DCHECK(offscreen_context_ && offscreen_context_->IsValid());
+  return offscreen_context_->ClearCurrent();
+}
+
 bool AndroidSurfaceGL::SetNativeWindow(
     fml::RefPtr<AndroidNativeWindow> window) {
   // In any case, we want to get rid of our current onscreen context.

shell/platform/android/android_surface_gl.h

@@ -40,6 +40,9 @@ class AndroidSurfaceGL final : public GPUSurfaceGLDelegate,
   // |shell::AndroidSurface|
   bool ResourceContextMakeCurrent() override;
 
+  // |shell::AndroidSurface|
+  bool ResourceContextClearCurrent() override;
+
   // |shell::AndroidSurface|
   bool SetNativeWindow(fml::RefPtr<AndroidNativeWindow> window) override;
 

shell/platform/android/android_surface_software.cc

@@ -52,6 +52,10 @@ bool AndroidSurfaceSoftware::ResourceContextMakeCurrent() {
   return false;
 }
 
+bool AndroidSurfaceSoftware::ResourceContextClearCurrent() {
+  return false;
+}
+
 std::unique_ptr<Surface> AndroidSurfaceSoftware::CreateGPUSurface() {
   if (!IsValid()) {
     return nullptr;

shell/platform/android/android_surface_software.h

@@ -26,6 +26,9 @@ class AndroidSurfaceSoftware final : public AndroidSurface,
   // |shell::AndroidSurface|
   bool ResourceContextMakeCurrent() override;
 
+  // |shell::AndroidSurface|
+  bool ResourceContextClearCurrent() override;
+
   // |shell::AndroidSurface|
   std::unique_ptr<Surface> CreateGPUSurface() override;
 

shell/platform/android/android_surface_vulkan.cc

@@ -65,6 +65,10 @@ bool AndroidSurfaceVulkan::ResourceContextMakeCurrent() {
   return false;
 }
 
+bool AndroidSurfaceVulkan::ResourceContextClearCurrent() {
+  return false;
+}
+
 // |shell::AndroidSurface|
 bool AndroidSurfaceVulkan::SetNativeWindow(
     fml::RefPtr<AndroidNativeWindow> window) {

shell/platform/android/platform_view_android.cc

@@ -385,6 +385,13 @@ sk_sp<GrContext> PlatformViewAndroid::CreateResourceContext() const {
   return resource_context;
 }
 
+// |shell::PlatformView|
+void PlatformViewAndroid::ReleaseResourceContext() const {
+  if (android_surface_) {
+    android_surface_->ResourceContextClearCurrent();
+  }
+}
+
 void PlatformViewAndroid::InstallFirstFrameCallback() {
   // On Platform Task Runner.
   SetNextFrameCallback(

shell/platform/android/platform_view_android.h

@@ -102,6 +102,9 @@ class PlatformViewAndroid final : public PlatformView {
   // |shell::PlatformView|
   sk_sp<GrContext> CreateResourceContext() const override;
 
+  // |shell::PlatformView|
+  void ReleaseResourceContext() const override;
+
   void InstallFirstFrameCallback();
 
   void FireFirstFrameCallback();