Make the context current before accessing GL in MakeSkiaGpuImage (flutter#40208)

Make the context current before accessing GL in MakeSkiaGpuImage

Author: dnfield

shell/common/BUILD.gn

@@ -328,5 +328,13 @@ if (enable_unittests) {
         deps += [ "//third_party/swiftshader" ]
       }
     }
+
+    if (shell_enable_gl) {
+      deps += [
+        "//third_party/angle:libEGL_static",
+        "//third_party/angle:libGLESv2_static",
+        "//third_party/swiftshader",
+      ]
+    }
   }
 }

shell/common/fixtures/shell_test.dart

@@ -354,6 +354,9 @@ void scene_with_red_box() {
   PlatformDispatcher.instance.scheduleFrame();
 }
 
+@pragma('vm:external-name', 'NativeOnBeforeToImageSync')
+external void onBeforeToImageSync();
+
 
 @pragma('vm:entry-point')
 Future<void> toImageSync() async {
@@ -362,6 +365,7 @@ Future<void> toImageSync() async {
   canvas.drawPaint(Paint()..color = const Color(0xFFAAAAAA));
   final Picture picture = recorder.endRecording();
 
+  onBeforeToImageSync();
   final Image image = picture.toImageSync(20, 25);
   void expect(Object? a, Object? b) {
     if (a != b) {

shell/common/rasterizer.cc

@@ -289,24 +289,27 @@ std::unique_ptr<Rasterizer::GpuImageResult> Rasterizer::MakeSkiaGpuImage(
   TRACE_EVENT0("flutter", "Rasterizer::MakeGpuImage");
   FML_DCHECK(display_list);
 
-// TODO(dnfield): the Linux embedding is in a rough state right now and
-// I can't seem to get the GPU path working on it.
-// https://github.com/flutter/flutter/issues/108835
-#if FML_OS_LINUX
-  return MakeBitmapImage(display_list, image_info);
-#endif
-
   std::unique_ptr<SnapshotDelegate::GpuImageResult> result;
   delegate_.GetIsGpuDisabledSyncSwitch()->Execute(
       fml::SyncSwitch::Handlers()
           .SetIfTrue([&result, &image_info, &display_list] {
+            // TODO(dnfield): This isn't safe if display_list contains any GPU
+            // resources like an SkImage_gpu.
             result = MakeBitmapImage(display_list, image_info);
           })
           .SetIfFalse([&result, &image_info, &display_list,
                        surface = surface_.get(),
                        gpu_image_behavior = gpu_image_behavior_] {
             if (!surface ||
                 gpu_image_behavior == MakeGpuImageBehavior::kBitmap) {
+              // TODO(dnfield): This isn't safe if display_list contains any GPU
+              // resources like an SkImage_gpu.
+              result = MakeBitmapImage(display_list, image_info);
+              return;
+            }
+
+            auto context_switch = surface->MakeRenderContextCurrent();
+            if (!context_switch->GetResult()) {
               result = MakeBitmapImage(display_list, image_info);
               return;
             }

shell/common/shell_unittests.cc

@@ -11,6 +11,10 @@
 #include <utility>
 #include <vector>
 
+#if SHELL_ENABLE_GL
+#include <EGL/egl.h>
+#endif  // SHELL_ENABLE_GL
+
 #include "assets/directory_asset_bundle.h"
 #include "common/graphics/persistent_cache.h"
 #include "flutter/flow/layers/backdrop_filter_layer.h"
@@ -3890,6 +3894,11 @@ TEST_F(ShellTest, PictureToImageSync) {
                   ShellTestPlatformView::BackendType::kGLBackend  //
       );
 
+  AddNativeCallback("NativeOnBeforeToImageSync",
+                    CREATE_NATIVE_ENTRY([&](auto args) {
+                      // nop
+                    }));
+
   fml::CountDownLatch latch(2);
   AddNativeCallback("NotifyNative", CREATE_NATIVE_ENTRY([&](auto args) {
                       // Teardown and set up rasterizer again.
@@ -3912,6 +3921,58 @@ TEST_F(ShellTest, PictureToImageSync) {
   DestroyShell(std::move(shell));
 }
 
+#if SHELL_ENABLE_GL
+// This test uses the GL backend and refers to symbols in egl.h
+TEST_F(ShellTest, PictureToImageSyncWithTrampledContext) {
+  // make it easier to trample the GL context by running on a single task
+  // runner.
+  ThreadHost thread_host("io.flutter.test." + GetCurrentTestName() + ".",
+                         ThreadHost::Type::Platform);
+  auto task_runner = thread_host.platform_thread->GetTaskRunner();
+  TaskRunners task_runners("test", task_runner, task_runner, task_runner,
+                           task_runner);
+
+  auto settings = CreateSettingsForFixture();
+  std::unique_ptr<Shell> shell =
+      CreateShell(settings,                                       //
+                  task_runners,                                   //
+                  false,                                          //
+                  nullptr,                                        //
+                  false,                                          //
+                  ShellTestPlatformView::BackendType::kGLBackend  //
+      );
+
+  AddNativeCallback(
+      "NativeOnBeforeToImageSync", CREATE_NATIVE_ENTRY([&](auto args) {
+        // Trample the GL context. If the rasterizer fails
+        // to make the right one current again, test will
+        // fail.
+        ::eglMakeCurrent(::eglGetCurrentDisplay(), NULL, NULL, NULL);
+      }));
+
+  fml::CountDownLatch latch(2);
+  AddNativeCallback("NotifyNative", CREATE_NATIVE_ENTRY([&](auto args) {
+                      // Teardown and set up rasterizer again.
+                      PlatformViewNotifyDestroyed(shell.get());
+                      PlatformViewNotifyCreated(shell.get());
+                      latch.CountDown();
+                    }));
+
+  ASSERT_NE(shell, nullptr);
+  ASSERT_TRUE(shell->IsSetup());
+  auto configuration = RunConfiguration::InferFromSettings(settings);
+  PlatformViewNotifyCreated(shell.get());
+  configuration.SetEntrypoint("toImageSync");
+  RunEngine(shell.get(), std::move(configuration));
+  PumpOneFrame(shell.get());
+
+  latch.Wait();
+
+  PlatformViewNotifyDestroyed(shell.get());
+  DestroyShell(std::move(shell), task_runners);
+}
+#endif  // SHELL_ENABLE_GL
+
 TEST_F(ShellTest, PluginUtilitiesCallbackHandleErrorHandling) {
   auto settings = CreateSettingsForFixture();
   std::unique_ptr<Shell> shell =