[Windows] Remove PlatformWindow and RenderTarget abstractions (#49312)

The Windows embedder has three ways to get an `HWND`:

1. `GetWindowHandle` which returns the `HWND`
2. `GetPlatformWindow` which returns the `HWND` wrapped as a `PlatformWindow`
3. `GetRenderTarget` which returns the `HWND` wrapped as a `RenderTarget`

These abstractions are no longer useful now that we removed the UWP embedder. This change removes `PlatformWindow` and `RenderTarget` and uses `HWND` directly.

This change is a refactoring with no semantic changes.

Author: loic-sharma

shell/platform/windows/angle_surface_manager.cc

@@ -229,10 +229,10 @@ void AngleSurfaceManager::CleanUp() {
   }
 }
 
-bool AngleSurfaceManager::CreateSurface(WindowsRenderTarget* render_target,
+bool AngleSurfaceManager::CreateSurface(HWND hwnd,
                                         EGLint width,
                                         EGLint height) {
-  if (!render_target || !initialize_succeeded_) {
+  if (!hwnd || !initialize_succeeded_) {
     return false;
   }
 
@@ -245,10 +245,9 @@ bool AngleSurfaceManager::CreateSurface(WindowsRenderTarget* render_target,
       EGL_FIXED_SIZE_ANGLE, EGL_TRUE, EGL_WIDTH, width,
       EGL_HEIGHT,           height,   EGL_NONE};
 
-  surface = eglCreateWindowSurface(
-      egl_display_, egl_config_,
-      static_cast<EGLNativeWindowType>(std::get<HWND>(*render_target)),
-      surfaceAttributes);
+  surface = eglCreateWindowSurface(egl_display_, egl_config_,
+                                   static_cast<EGLNativeWindowType>(hwnd),
+                                   surfaceAttributes);
   if (surface == EGL_NO_SURFACE) {
     LogEglError("Surface creation failed.");
     return false;
@@ -260,7 +259,7 @@ bool AngleSurfaceManager::CreateSurface(WindowsRenderTarget* render_target,
   return true;
 }
 
-void AngleSurfaceManager::ResizeSurface(WindowsRenderTarget* render_target,
+void AngleSurfaceManager::ResizeSurface(HWND hwnd,
                                         EGLint width,
                                         EGLint height,
                                         bool vsync_enabled) {
@@ -275,7 +274,7 @@ void AngleSurfaceManager::ResizeSurface(WindowsRenderTarget* render_target,
     // See: https://github.com/flutter/flutter/issues/79427
     ClearContext();
     DestroySurface();
-    if (!CreateSurface(render_target, width, height)) {
+    if (!CreateSurface(hwnd, width, height)) {
       FML_LOG(ERROR)
           << "AngleSurfaceManager::ResizeSurface failed to create surface";
     }

shell/platform/windows/angle_surface_manager.h

@@ -33,22 +33,20 @@ class AngleSurfaceManager {
 
   // Creates an EGLSurface wrapper and backing DirectX 11 SwapChain
   // associated with window, in the appropriate format for display.
-  // Target represents the visual entity to bind to. Width and
-  // height represent dimensions surface is created at.
+  // HWND is the window backing the surface. Width and height represent
+  // dimensions surface is created at.
   //
   // After the surface is created, |SetVSyncEnabled| should be called on a
   // thread that can bind the |egl_context_|.
-  virtual bool CreateSurface(WindowsRenderTarget* render_target,
-                             EGLint width,
-                             EGLint height);
+  virtual bool CreateSurface(HWND hwnd, EGLint width, EGLint height);
 
   // Resizes backing surface from current size to newly requested size
   // based on width and height for the specific case when width and height do
   // not match current surface dimensions. Target represents the visual entity
   // to bind to.
   //
   // This binds |egl_context_| to the current thread.
-  virtual void ResizeSurface(WindowsRenderTarget* render_target,
+  virtual void ResizeSurface(HWND hwnd,
                              EGLint width,
                              EGLint height,
                              bool enable_vsync);

shell/platform/windows/compositor_opengl_unittests.cc

@@ -104,7 +104,7 @@ class CompositorOpenGLTest : public WindowsTest {
 
     auto window = std::make_unique<MockWindowBindingHandler>();
     EXPECT_CALL(*window.get(), SetView).Times(1);
-    EXPECT_CALL(*window.get(), GetRenderTarget).WillRepeatedly(Return(nullptr));
+    EXPECT_CALL(*window.get(), GetWindowHandle).WillRepeatedly(Return(nullptr));
 
     view_ = std::make_unique<MockFlutterWindowsView>(std::move(window));
 

shell/platform/windows/compositor_software_unittests.cc

@@ -56,7 +56,7 @@ class CompositorSoftwareTest : public WindowsTest {
 
     auto window = std::make_unique<MockWindowBindingHandler>();
     EXPECT_CALL(*window.get(), SetView).Times(1);
-    EXPECT_CALL(*window.get(), GetRenderTarget).WillRepeatedly(Return(nullptr));
+    EXPECT_CALL(*window.get(), GetWindowHandle).WillRepeatedly(Return(nullptr));
 
     engine_ = builder.Build();
     view_ = std::make_unique<MockFlutterWindowsView>(std::move(window));

shell/platform/windows/cursor_handler_unittests.cc

@@ -76,7 +76,6 @@ class CursorHandlerTest : public WindowsTest {
 
     window_ = window.get();
     EXPECT_CALL(*window_, SetView).Times(1);
-    EXPECT_CALL(*window_, GetRenderTarget).WillOnce(Return(nullptr));
 
     engine_ = builder.Build();
     view_ = std::make_unique<FlutterWindowsView>(std::move(window));

shell/platform/windows/flutter_platform_node_delegate_windows.cc

@@ -87,8 +87,8 @@ gfx::Rect FlutterPlatformNodeDelegateWindows::GetBoundsRect(
       coordinate_system, clipping_behavior, offscreen_result);
   POINT origin{bounds.x(), bounds.y()};
   POINT extent{bounds.x() + bounds.width(), bounds.y() + bounds.height()};
-  ClientToScreen(view_->GetPlatformWindow(), &origin);
-  ClientToScreen(view_->GetPlatformWindow(), &extent);
+  ClientToScreen(view_->GetWindowHandle(), &origin);
+  ClientToScreen(view_->GetWindowHandle(), &extent);
   return gfx::Rect(origin.x, origin.y, extent.x - origin.x,
                    extent.y - origin.y);
 }
@@ -107,7 +107,7 @@ void FlutterPlatformNodeDelegateWindows::SetFocus() {
 
 gfx::AcceleratedWidget
 FlutterPlatformNodeDelegateWindows::GetTargetForNativeAccessibilityEvent() {
-  return view_->GetPlatformWindow();
+  return view_->GetWindowHandle();
 }
 
 ui::AXPlatformNode* FlutterPlatformNodeDelegateWindows::GetPlatformNode()

shell/platform/windows/flutter_window.cc

@@ -164,14 +164,6 @@ void FlutterWindow::SetView(WindowBindingHandlerDelegate* window) {
   }
 }
 
-WindowsRenderTarget FlutterWindow::GetRenderTarget() {
-  return WindowsRenderTarget(GetWindowHandle());
-}
-
-PlatformWindow FlutterWindow::GetPlatformWindow() {
-  return GetWindowHandle();
-}
-
 float FlutterWindow::GetDpiScale() {
   return static_cast<float>(GetCurrentDPI()) / static_cast<float>(base_dpi);
 }
@@ -408,7 +400,7 @@ void FlutterWindow::OnWindowStateEvent(WindowStateEvent event) {
       focused_ = false;
       break;
   }
-  HWND hwnd = GetPlatformWindow();
+  HWND hwnd = GetWindowHandle();
   if (hwnd && binding_handler_delegate_) {
     binding_handler_delegate_->OnWindowStateEvent(hwnd, event);
   }

shell/platform/windows/flutter_window.h

@@ -50,8 +50,6 @@ class FlutterWindow : public KeyboardManager::WindowDelegate,
                        unsigned int width,
                        unsigned int height);
 
-  HWND GetWindowHandle();
-
   // |KeyboardManager::WindowDelegate|
   virtual BOOL Win32PeekMessage(LPMSG lpMsg,
                                 UINT wMsgFilterMin,
@@ -155,10 +153,7 @@ class FlutterWindow : public KeyboardManager::WindowDelegate,
   virtual void SetView(WindowBindingHandlerDelegate* view) override;
 
   // |FlutterWindowBindingHandler|
-  virtual WindowsRenderTarget GetRenderTarget() override;
-
-  // |FlutterWindowBindingHandler|
-  virtual PlatformWindow GetPlatformWindow() override;
+  virtual HWND GetWindowHandle() override;
 
   // |FlutterWindowBindingHandler|
   virtual float GetDpiScale() override;

shell/platform/windows/flutter_window_unittests.cc

@@ -72,7 +72,7 @@ class MockFlutterWindow : public FlutterWindow {
   MOCK_METHOD(UINT, Win32DispatchMessage, (UINT, WPARAM, LPARAM), (override));
   MOCK_METHOD(BOOL, Win32PeekMessage, (LPMSG, UINT, UINT, UINT), (override));
   MOCK_METHOD(uint32_t, Win32MapVkToChar, (uint32_t), (override));
-  MOCK_METHOD(HWND, GetPlatformWindow, (), (override));
+  MOCK_METHOD(HWND, GetWindowHandle, (), (override));
   MOCK_METHOD(ui::AXFragmentRootDelegateWin*,
               GetAxFragmentRootDelegate,
               (),
@@ -341,7 +341,7 @@ TEST(FlutterWindowTest, AlertNode) {
 
 TEST(FlutterWindowTest, LifecycleFocusMessages) {
   MockFlutterWindow win32window;
-  EXPECT_CALL(win32window, GetPlatformWindow)
+  EXPECT_CALL(win32window, GetWindowHandle)
       .WillRepeatedly(Return(reinterpret_cast<HWND>(1)));
   MockWindowBindingHandlerDelegate delegate;
 
@@ -373,7 +373,7 @@ TEST(FlutterWindowTest, LifecycleFocusMessages) {
 
 TEST(FlutterWindowTest, CachedLifecycleMessage) {
   MockFlutterWindow win32window;
-  EXPECT_CALL(win32window, GetPlatformWindow)
+  EXPECT_CALL(win32window, GetWindowHandle)
       .WillRepeatedly(Return(reinterpret_cast<HWND>(1)));
   EXPECT_CALL(win32window, OnWindowStateEvent)
       .WillRepeatedly([&](WindowStateEvent event) {
@@ -413,8 +413,8 @@ TEST(FlutterWindowTest, PosthumousWindowMessage) {
 
   {
     MockFlutterWindow win32window(false);
-    EXPECT_CALL(win32window, GetPlatformWindow).WillRepeatedly([&]() {
-      return win32window.FlutterWindow::GetPlatformWindow();
+    EXPECT_CALL(win32window, GetWindowHandle).WillRepeatedly([&]() {
+      return win32window.FlutterWindow::GetWindowHandle();
     });
     EXPECT_CALL(win32window, OnWindowStateEvent)
         .WillRepeatedly([&](WindowStateEvent event) {
@@ -423,7 +423,7 @@ TEST(FlutterWindowTest, PosthumousWindowMessage) {
     EXPECT_CALL(win32window, OnResize).Times(AnyNumber());
     win32window.SetView(&delegate);
     win32window.InitializeChild("Title", 1, 1);
-    hwnd = win32window.GetPlatformWindow();
+    hwnd = win32window.GetWindowHandle();
     SendMessage(hwnd, WM_SIZE, 0, MAKEWORD(1, 1));
     SendMessage(hwnd, WM_SETFOCUS, 0, 0);
 

shell/platform/windows/flutter_windows.cc

@@ -211,7 +211,7 @@ void FlutterDesktopEngineSetNextFrameCallback(FlutterDesktopEngineRef engine,
 }
 
 HWND FlutterDesktopViewGetHWND(FlutterDesktopViewRef view) {
-  return ViewFromHandle(view)->GetPlatformWindow();
+  return ViewFromHandle(view)->GetWindowHandle();
 }
 
 IDXGIAdapter* FlutterDesktopViewGetGraphicsAdapter(FlutterDesktopViewRef view) {