Add windows plugin texture support

ci/licenses_golden/licenses_flutter

@@ -897,6 +897,7 @@ FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/include/flutter/
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/include/flutter/standard_codec_serializer.h
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/include/flutter/standard_message_codec.h
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/include/flutter/standard_method_codec.h
+FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/include/flutter/texture_registrar.h
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/method_call_unittests.cc
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/method_channel_unittests.cc
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/method_result_functions_unittests.cc
@@ -905,6 +906,8 @@ FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/plugin_registrar
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/standard_codec.cc
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/standard_message_codec_unittests.cc
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/standard_method_codec_unittests.cc
+FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/texture_registrar_impl.h
+FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/texture_registrar_unittests.cc
 FILE: ../../../flutter/shell/platform/common/cpp/engine_switches.cc
 FILE: ../../../flutter/shell/platform/common/cpp/engine_switches.h
 FILE: ../../../flutter/shell/platform/common/cpp/engine_switches_unittests.cc
@@ -1432,13 +1435,18 @@ FILE: ../../../flutter/shell/platform/windows/client_wrapper/include/flutter/plu
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/plugin_registrar_windows_unittests.cc
 FILE: ../../../flutter/shell/platform/windows/cursor_handler.cc
 FILE: ../../../flutter/shell/platform/windows/cursor_handler.h
+FILE: ../../../flutter/shell/platform/windows/external_texture_gl.cc
+FILE: ../../../flutter/shell/platform/windows/external_texture_gl.h
 FILE: ../../../flutter/shell/platform/windows/flutter_project_bundle.cc
 FILE: ../../../flutter/shell/platform/windows/flutter_project_bundle.h
 FILE: ../../../flutter/shell/platform/windows/flutter_project_bundle_unittests.cc
 FILE: ../../../flutter/shell/platform/windows/flutter_windows.cc
 FILE: ../../../flutter/shell/platform/windows/flutter_windows_engine.cc
 FILE: ../../../flutter/shell/platform/windows/flutter_windows_engine.h
 FILE: ../../../flutter/shell/platform/windows/flutter_windows_engine_unittests.cc
+FILE: ../../../flutter/shell/platform/windows/flutter_windows_texture_registrar.cc
+FILE: ../../../flutter/shell/platform/windows/flutter_windows_texture_registrar.h
+FILE: ../../../flutter/shell/platform/windows/flutter_windows_texture_registrar_unittests.cc
 FILE: ../../../flutter/shell/platform/windows/flutter_windows_view.cc
 FILE: ../../../flutter/shell/platform/windows/flutter_windows_view.h
 FILE: ../../../flutter/shell/platform/windows/flutter_windows_win32.cc

shell/platform/common/cpp/client_wrapper/BUILD.gn

@@ -51,6 +51,7 @@ executable("client_wrapper_unittests") {
     "standard_method_codec_unittests.cc",
     "testing/test_codec_extensions.cc",
     "testing/test_codec_extensions.h",
+    "texture_registrar_unittests.cc",
   ]
 
   deps = [

shell/platform/common/cpp/client_wrapper/core_implementations.cc

@@ -15,9 +15,11 @@
 
 #include <cassert>
 #include <iostream>
+#include <variant>
 
 #include "binary_messenger_impl.h"
 #include "include/flutter/engine_method_result.h"
+#include "texture_registrar_impl.h"
 
 namespace flutter {
 
@@ -146,4 +148,44 @@ void ReplyManager::SendResponseData(const std::vector<uint8_t>* data) {
 
 }  // namespace internal
 
+// ========== texture_registrar_impl.h ==========
+
+TextureRegistrarImpl::TextureRegistrarImpl(
+    FlutterDesktopTextureRegistrarRef texture_registrar_ref)
+    : texture_registrar_ref_(texture_registrar_ref) {}
+
+TextureRegistrarImpl::~TextureRegistrarImpl() = default;
+
+int64_t TextureRegistrarImpl::RegisterTexture(TextureVariant* texture) {
+  if (auto pixel_buffer_texture = std::get_if<PixelBufferTexture>(texture)) {
+    FlutterDesktopTextureInfo info = {};
+    info.type = kFlutterDesktopPixelBufferTexture;
+    info.pixel_buffer_config.user_data = pixel_buffer_texture;
+    info.pixel_buffer_config.callback =
+        [](size_t width, size_t height,
+           void* user_data) -> const FlutterDesktopPixelBuffer* {
+      auto texture = static_cast<PixelBufferTexture*>(user_data);
+      auto buffer = texture->CopyPixelBuffer(width, height);
+      return buffer;
+    };
+
+    int64_t texture_id = FlutterDesktopTextureRegistrarRegisterExternalTexture(
+        texture_registrar_ref_, &info);
+    return texture_id;
+  }
+
+  std::cerr << "Attempting to register unknown texture variant." << std::endl;
+  return -1;
+}  // namespace flutter
+
+bool TextureRegistrarImpl::MarkTextureFrameAvailable(int64_t texture_id) {
+  return FlutterDesktopTextureRegistrarMarkExternalTextureFrameAvailable(
+      texture_registrar_ref_, texture_id);
+}
+
+bool TextureRegistrarImpl::UnregisterTexture(int64_t texture_id) {
+  return FlutterDesktopTextureRegistrarUnregisterExternalTexture(
+      texture_registrar_ref_, texture_id);
+}
+
 }  // namespace flutter

shell/platform/common/cpp/client_wrapper/core_wrapper_files.gni

@@ -24,6 +24,7 @@ core_cpp_client_wrapper_includes =
                     "include/flutter/standard_codec_serializer.h",
                     "include/flutter/standard_message_codec.h",
                     "include/flutter/standard_method_codec.h",
+                    "include/flutter/texture_registrar.h",
                   ],
                   "abspath")
 
@@ -34,6 +35,7 @@ core_cpp_client_wrapper_internal_headers =
     get_path_info([
                     "binary_messenger_impl.h",
                     "byte_buffer_streams.h",
+                    "texture_registrar_impl.h",
                   ],
                   "abspath")
 

shell/platform/common/cpp/client_wrapper/include/flutter/plugin_registrar.h

@@ -13,6 +13,7 @@
 #include <string>
 
 #include "binary_messenger.h"
+#include "texture_registrar.h"
 
 namespace flutter {
 
@@ -41,6 +42,10 @@ class PluginRegistrar {
   // This pointer will remain valid for the lifetime of this instance.
   BinaryMessenger* messenger() { return messenger_.get(); }
 
+  // Returns the texture registrar to use for the plugin to render a pixel
+  // buffer.
+  TextureRegistrar* texture_registrar() { return texture_registrar_.get(); }
+
   // Takes ownership of |plugin|.
   //
   // Plugins are not required to call this method if they have other lifetime
@@ -62,6 +67,8 @@ class PluginRegistrar {
 
   std::unique_ptr<BinaryMessenger> messenger_;
 
+  std::unique_ptr<TextureRegistrar> texture_registrar_;
+
   // Plugins registered for ownership.
   std::set<std::unique_ptr<Plugin>> plugins_;
 };

shell/platform/common/cpp/client_wrapper/include/flutter/texture_registrar.h

@@ -0,0 +1,75 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_SHELL_PLATFORM_COMMON_CPP_CLIENT_WRAPPER_INCLUDE_FLUTTER_TEXTURE_REGISTRAR_H_
+#define FLUTTER_SHELL_PLATFORM_COMMON_CPP_CLIENT_WRAPPER_INCLUDE_FLUTTER_TEXTURE_REGISTRAR_H_
+
+#include <flutter_texture_registrar.h>
+
+#include <cstdint>
+#include <functional>
+#include <memory>
+#include <variant>
+
+namespace flutter {
+
+// A pixel buffer texture.
+class PixelBufferTexture {
+ public:
+  // A callback used for retrieving pixel buffers.
+  typedef std::function<const FlutterDesktopPixelBuffer*(size_t width,
+                                                         size_t height)>
+      CopyBufferCallback;
+
+  // Creates a pixel buffer texture that uses the provided |copy_buffer_cb| to
+  // retrieve the buffer.
+  // As the callback is usually invoked from the render thread, the callee must
+  // take care of proper synchronization. It also needs to be ensured that the
+  // returned buffer isn't released prior to unregistering this texture.
+  PixelBufferTexture(CopyBufferCallback copy_buffer_callback)
+      : copy_buffer_callback_(copy_buffer_callback) {}
+
+  // Returns the callback-provided FlutterDesktopPixelBuffer that contains the
+  // actual pixel data. The intended surface size is specified by |width| and
+  // |height|.
+  const FlutterDesktopPixelBuffer* CopyPixelBuffer(size_t width,
+                                                   size_t height) const {
+    return copy_buffer_callback_(width, height);
+  }
+
+ private:
+  const CopyBufferCallback copy_buffer_callback_;
+};
+
+// The available texture variants.
+// Only PixelBufferTexture is currently implemented.
+// Other variants are expected to be added in the future.
+typedef std::variant<PixelBufferTexture> TextureVariant;
+
+// An object keeping track of external textures.
+//
+// Thread safety:
+// It's safe to call the member methods from any thread.
+class TextureRegistrar {
+ public:
+  virtual ~TextureRegistrar() = default;
+
+  // Registers a |texture| object and returns the ID for that texture.
+  virtual int64_t RegisterTexture(TextureVariant* texture) = 0;
+
+  // Notifies the flutter engine that the texture object corresponding
+  // to |texure_id| needs to render a new frame.
+  //
+  // For PixelBufferTextures, this will effectively make the engine invoke
+  // the callback that was provided upon creating the texture.
+  virtual bool MarkTextureFrameAvailable(int64_t texture_id) = 0;
+
+  // Unregisters an existing Texture object.
+  // Textures must not be unregistered while they're in use.
+  virtual bool UnregisterTexture(int64_t texture_id) = 0;
+};
+
+}  // namespace flutter
+
+#endif  // FLUTTER_SHELL_PLATFORM_COMMON_CPP_CLIENT_WRAPPER_INCLUDE_FLUTTER_TEXTURE_REGISTRAR_H_

shell/platform/common/cpp/client_wrapper/plugin_registrar.cc

@@ -10,6 +10,7 @@
 #include "binary_messenger_impl.h"
 #include "include/flutter/engine_method_result.h"
 #include "include/flutter/method_channel.h"
+#include "texture_registrar_impl.h"
 
 namespace flutter {
 
@@ -19,6 +20,11 @@ PluginRegistrar::PluginRegistrar(FlutterDesktopPluginRegistrarRef registrar)
     : registrar_(registrar) {
   auto core_messenger = FlutterDesktopPluginRegistrarGetMessenger(registrar_);
   messenger_ = std::make_unique<BinaryMessengerImpl>(core_messenger);
+
+  auto texture_registrar =
+      FlutterDesktopRegistrarGetTextureRegistrar(registrar_);
+  texture_registrar_ =
+      std::make_unique<TextureRegistrarImpl>(texture_registrar);
 }
 
 PluginRegistrar::~PluginRegistrar() {

shell/platform/common/cpp/client_wrapper/plugin_registrar_unittests.cc

@@ -214,4 +214,15 @@ TEST(PluginRegistrarTest, ManagerRemovesOnDestruction) {
             nullptr);
 }
 
+// Tests that the texture registrar getter returns a non-null TextureRegistrar
+TEST(PluginRegistrarTest, TextureRegistrarNotNull) {
+  auto dummy_registrar_handle =
+      reinterpret_cast<FlutterDesktopPluginRegistrarRef>(1);
+  PluginRegistrar registrar(dummy_registrar_handle);
+
+  TextureRegistrar* texture_registrar = registrar.texture_registrar();
+
+  ASSERT_NE(texture_registrar, nullptr);
+}
+
 }  // namespace flutter

shell/platform/common/cpp/client_wrapper/testing/stub_flutter_api.cc

@@ -92,3 +92,41 @@ void FlutterDesktopMessengerSetCallback(FlutterDesktopMessengerRef messenger,
     s_stub_implementation->MessengerSetCallback(channel, callback, user_data);
   }
 }
+
+FlutterDesktopTextureRegistrarRef FlutterDesktopRegistrarGetTextureRegistrar(
+    FlutterDesktopPluginRegistrarRef registrar) {
+  return reinterpret_cast<FlutterDesktopTextureRegistrarRef>(1);
+}
+
+int64_t FlutterDesktopTextureRegistrarRegisterExternalTexture(
+    FlutterDesktopTextureRegistrarRef texture_registrar,
+    const FlutterDesktopTextureInfo* info) {
+  uint64_t result = -1;
+  if (s_stub_implementation) {
+    result =
+        s_stub_implementation->TextureRegistrarRegisterExternalTexture(info);
+  }
+  return result;
+}
+
+bool FlutterDesktopTextureRegistrarUnregisterExternalTexture(
+    FlutterDesktopTextureRegistrarRef texture_registrar,
+    int64_t texture_id) {
+  bool result = false;
+  if (s_stub_implementation) {
+    result = s_stub_implementation->TextureRegistrarUnregisterExternalTexture(
+        texture_id);
+  }
+  return result;
+}
+
+bool FlutterDesktopTextureRegistrarMarkExternalTextureFrameAvailable(
+    FlutterDesktopTextureRegistrarRef texture_registrar,
+    int64_t texture_id) {
+  bool result = false;
+  if (s_stub_implementation) {
+    result = s_stub_implementation->TextureRegistrarMarkTextureFrameAvailable(
+        texture_id);
+  }
+  return result;
+}

shell/platform/common/cpp/client_wrapper/testing/stub_flutter_api.h

@@ -64,6 +64,22 @@ class StubFlutterApi {
   virtual void MessengerSetCallback(const char* channel,
                                     FlutterDesktopMessageCallback callback,
                                     void* user_data) {}
+
+  // Called for FlutterDesktopRegisterExternalTexture.
+  virtual int64_t TextureRegistrarRegisterExternalTexture(
+      const FlutterDesktopTextureInfo* info) {
+    return -1;
+  }
+
+  // Called for FlutterDesktopUnregisterExternalTexture.
+  virtual bool TextureRegistrarUnregisterExternalTexture(int64_t texture_id) {
+    return false;
+  }
+
+  // Called for FlutterDesktopMarkExternalTextureFrameAvailable.
+  virtual bool TextureRegistrarMarkTextureFrameAvailable(int64_t texture_id) {
+    return false;
+  }
 };
 
 // A test helper that owns a stub implementation, making it the test stub for

shell/platform/common/cpp/client_wrapper/texture_registrar_impl.h

@@ -0,0 +1,40 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_SHELL_PLATFORM_COMMON_CPP_CLIENT_WRAPPER_TEXTURE_REGISTRAR_IMPL_H_
+#define FLUTTER_SHELL_PLATFORM_COMMON_CPP_CLIENT_WRAPPER_TEXTURE_REGISTRAR_IMPL_H_
+
+#include "include/flutter/texture_registrar.h"
+
+namespace flutter {
+
+// Wrapper around a FlutterDesktopTextureRegistrarRef that implements the
+// TextureRegistrar API.
+class TextureRegistrarImpl : public TextureRegistrar {
+ public:
+  explicit TextureRegistrarImpl(
+      FlutterDesktopTextureRegistrarRef texture_registrar_ref);
+  virtual ~TextureRegistrarImpl();
+
+  // Prevent copying.
+  TextureRegistrarImpl(TextureRegistrarImpl const&) = delete;
+  TextureRegistrarImpl& operator=(TextureRegistrarImpl const&) = delete;
+
+  // |flutter::TextureRegistrar|
+  int64_t RegisterTexture(TextureVariant* texture) override;
+
+  // |flutter::TextureRegistrar|
+  bool MarkTextureFrameAvailable(int64_t texture_id) override;
+
+  // |flutter::TextureRegistrar|
+  bool UnregisterTexture(int64_t texture_id) override;
+
+ private:
+  // Handle for interacting with the C API.
+  FlutterDesktopTextureRegistrarRef texture_registrar_ref_;
+};
+
+}  // namespace flutter
+
+#endif  // FLUTTER_SHELL_PLATFORM_COMMON_CPP_CLIENT_WRAPPER_TEXTURE_REGISTRAR_IMPL_H_