Detach the EGL surface from the GPU thread and then destroy it during the...

Detach the EGL surface from the GPU thread and then destroy it during the FlutterView surfaceDestroyed callback (#3316)

Fixes https://github.com/flutter/flutter/issues/7147

shell/common/null_rasterizer.cc

@@ -12,12 +12,17 @@ void NullRasterizer::Setup(
     std::unique_ptr<Surface> surface_or_null,
     ftl::Closure rasterizer_continuation,
     ftl::AutoResetWaitableEvent* setup_completion_event) {
+  surface_ = std::move(surface_or_null);
   rasterizer_continuation();
   setup_completion_event->Signal();
 }
 
 void NullRasterizer::Teardown(
     ftl::AutoResetWaitableEvent* teardown_completion_event) {
+  if (surface_) {
+    surface_->Teardown();
+    surface_.reset();
+  }
   teardown_completion_event->Signal();
 }
 

shell/common/null_rasterizer.h

@@ -32,6 +32,7 @@ class NullRasterizer : public Rasterizer {
 
  private:
   ftl::WeakPtrFactory<NullRasterizer> weak_factory_;
+  std::unique_ptr<Surface> surface_;
 
   FTL_DISALLOW_COPY_AND_ASSIGN(NullRasterizer);
 };

shell/common/surface.h

@@ -39,6 +39,8 @@ class Surface {
 
   virtual bool Setup() = 0;
 
+  virtual void Teardown() = 0;
+
   virtual bool IsValid() = 0;
 
   virtual std::unique_ptr<SurfaceFrame> AcquireFrame(const SkISize& size) = 0;

shell/gpu/gpu_rasterizer.cc

@@ -65,7 +65,10 @@ void GPURasterizer::Clear(SkColor color, const SkISize& size) {
 
 void GPURasterizer::Teardown(
     ftl::AutoResetWaitableEvent* teardown_completion_event) {
-  surface_.reset();
+  if (surface_) {
+    surface_->Teardown();
+    surface_.reset();
+  }
   last_layer_tree_.reset();
   compositor_context_.OnGrContextDestroyed();
   teardown_completion_event->Signal();

shell/gpu/gpu_surface_gl.cc

@@ -94,6 +94,10 @@ bool GPUSurfaceGL::Setup() {
   return true;
 }
 
+void GPUSurfaceGL::Teardown() {
+  delegate_->GLContextClearCurrent();
+}
+
 bool GPUSurfaceGL::IsValid() {
   return context_ != nullptr;
 }

shell/gpu/gpu_surface_gl.h

@@ -31,6 +31,8 @@ class GPUSurfaceGL : public Surface {
 
   bool Setup() override;
 
+  void Teardown() override;
+
   bool IsValid() override;
 
   std::unique_ptr<SurfaceFrame> AcquireFrame(const SkISize& size) override;

shell/platform/android/android_surface_gl.cc

@@ -79,6 +79,10 @@ bool AndroidSurfaceGL::SetNativeWindowForOnScreenContext(
   return true;
 }
 
+void AndroidSurfaceGL::TeardownOnScreenContext() {
+  onscreen_context_ = nullptr;
+}
+
 bool AndroidSurfaceGL::IsValid() const {
   if (!onscreen_context_ || !offscreen_context_) {
     return false;

shell/platform/android/android_surface_gl.h

@@ -24,6 +24,8 @@ class AndroidSurfaceGL : public GPUSurfaceGLDelegate {
       AndroidNativeWindow window,
       PlatformView::SurfaceConfig onscreen_config);
 
+  void TeardownOnScreenContext();
+
   bool IsValid() const;
 
   SkISize OnScreenSurfaceSize() const;

shell/platform/android/platform_view_android.cc

@@ -319,6 +319,7 @@ void PlatformViewAndroid::SetSemanticsEnabled(JNIEnv* env,
 
 void PlatformViewAndroid::ReleaseSurface() {
   NotifyDestroyed();
+  surface_gl_->TeardownOnScreenContext();
 }
 
 VsyncWaiter* PlatformViewAndroid::GetVsyncWaiter() {