Refactor Win32FlutterWindow in preparation for UWP windowing implementation

shell/platform/windows/BUILD.gn

@@ -41,20 +41,23 @@ source_set("flutter_windows_source") {
   sources = [
     "angle_surface_manager.cc",
     "angle_surface_manager.h",
-    "dpi_utils.cc",
-    "dpi_utils.h",
     "flutter_windows.cc",
+    "flutter_windows_view.cc",
+    "flutter_windows_view.h",
     "key_event_handler.cc",
     "key_event_handler.h",
     "keyboard_hook_handler.h",
-    "platform_handler.cc",
-    "platform_handler.h",
     "string_conversion.cc",
     "string_conversion.h",
     "text_input_plugin.cc",
     "text_input_plugin.h",
+    "window_binding_handler.h",
+    "win32_dpi_utils.cc",
+    "win32_dpi_utils.h",
     "win32_flutter_window.cc",
     "win32_flutter_window.h",
+    "win32_platform_handler.cc",
+    "win32_platform_handler.h",
     "win32_task_runner.cc",
     "win32_task_runner.h",
     "win32_window.cc",
@@ -110,12 +113,12 @@ executable("flutter_windows_unittests") {
   testonly = true
 
   sources = [
-    "dpi_utils_unittests.cc",
     "string_conversion_unittests.cc",
     "testing/win32_flutter_window_test.cc",
     "testing/win32_flutter_window_test.h",
     "testing/win32_window_test.cc",
     "testing/win32_window_test.h",
+    "win32_dpi_utils_unittests.cc",
     "win32_flutter_window_unittests.cc",
     "win32_window_unittests.cc",
   ]

shell/platform/windows/angle_surface_manager.cc

@@ -169,18 +169,20 @@ void AngleSurfaceManager::CleanUp() {
   }
 }
 
-EGLSurface AngleSurfaceManager::CreateSurface(HWND window) {
-  if (!window || !initialize_succeeded_) {
+EGLSurface AngleSurfaceManager::CreateSurface(
+    WindowsRenderTarget* render_target) {
+  if (!render_target || !initialize_succeeded_) {
     return EGL_NO_SURFACE;
   }
 
   EGLSurface surface = EGL_NO_SURFACE;
 
   const EGLint surfaceAttributes[] = {EGL_NONE};
 
-  surface = eglCreateWindowSurface(egl_display_, egl_config_,
-                                   static_cast<EGLNativeWindowType>(window),
-                                   surfaceAttributes);
+  surface = eglCreateWindowSurface(
+      egl_display_, egl_config_,
+      static_cast<EGLNativeWindowType>(render_target->GetWindowHandle()),
+      surfaceAttributes);
   if (surface == EGL_NO_SURFACE) {
     std::cerr << "Surface creation failed." << std::endl;
   }

shell/platform/windows/angle_surface_manager.h

@@ -15,6 +15,8 @@
 // Windows platform specific includes
 #include <windows.h>
 
+#include "window_binding_handler.h"
+
 namespace flutter {
 
 // An manager for inializing ANGLE correctly and using it to create and
@@ -29,9 +31,9 @@ class AngleSurfaceManager {
   AngleSurfaceManager& operator=(const AngleSurfaceManager&) = delete;
 
   // Creates and returns an EGLSurface wrapper and backing DirectX 11 SwapChain
-  // asociated with window, in the appropriate format for display in a
-  // HWND-backed window.
-  EGLSurface CreateSurface(HWND window);
+  // asociated with window, in the appropriate format for display.
+  // Target represents the visual entity to bind to.
+  EGLSurface CreateSurface(WindowsRenderTarget* render_target);
 
   // queries EGL for the dimensions of surface in physical
   // pixels returning width and height as out params.

shell/platform/windows/flutter_windows.cc

@@ -19,13 +19,15 @@
 #include "flutter/shell/platform/common/cpp/incoming_message_dispatcher.h"
 #include "flutter/shell/platform/common/cpp/path_utils.h"
 #include "flutter/shell/platform/embedder/embedder.h"
-#include "flutter/shell/platform/windows/dpi_utils.h"
+#include "flutter/shell/platform/windows/flutter_windows_view.h"
 #include "flutter/shell/platform/windows/key_event_handler.h"
 #include "flutter/shell/platform/windows/keyboard_hook_handler.h"
-#include "flutter/shell/platform/windows/platform_handler.h"
 #include "flutter/shell/platform/windows/text_input_plugin.h"
+#include "flutter/shell/platform/windows/win32_dpi_utils.h"
 #include "flutter/shell/platform/windows/win32_flutter_window.h"
+#include "flutter/shell/platform/windows/win32_platform_handler.h"
 #include "flutter/shell/platform/windows/win32_task_runner.h"
+#include "flutter/shell/platform/windows/window_binding_handler.h"
 #include "flutter/shell/platform/windows/window_state.h"
 
 static_assert(FLUTTER_ENGINE_VERSION == 1, "");
@@ -66,7 +68,7 @@ UniqueAotDataPtr LoadAotData(std::filesystem::path aot_data_path) {
 // Returns the state object for the engine, or null on failure to start the
 // engine.
 static std::unique_ptr<FlutterDesktopEngineState> RunFlutterEngine(
-    flutter::Win32FlutterWindow* window,
+    flutter::FlutterWindowsView* view,
     const FlutterDesktopEngineProperties& engine_properties) {
   auto state = std::make_unique<FlutterDesktopEngineState>();
 
@@ -79,22 +81,22 @@ static std::unique_ptr<FlutterDesktopEngineState> RunFlutterEngine(
                 &engine_properties.switches[engine_properties.switches_count]);
   }
 
-  window->CreateRenderSurface();
+  view->CreateRenderSurface();
 
   // Provide the necessary callbacks for rendering within a win32 child window.
   FlutterRendererConfig config = {};
   config.type = kOpenGL;
   config.open_gl.struct_size = sizeof(config.open_gl);
   config.open_gl.make_current = [](void* user_data) -> bool {
-    auto host = static_cast<flutter::Win32FlutterWindow*>(user_data);
+    auto host = static_cast<flutter::FlutterWindowsView*>(user_data);
     return host->MakeCurrent();
   };
   config.open_gl.clear_current = [](void* user_data) -> bool {
-    auto host = static_cast<flutter::Win32FlutterWindow*>(user_data);
+    auto host = static_cast<flutter::FlutterWindowsView*>(user_data);
     return host->ClearContext();
   };
   config.open_gl.present = [](void* user_data) -> bool {
-    auto host = static_cast<flutter::Win32FlutterWindow*>(user_data);
+    auto host = static_cast<flutter::FlutterWindowsView*>(user_data);
     return host->SwapBuffers();
   };
   config.open_gl.fbo_callback = [](void* user_data) -> uint32_t { return 0; };
@@ -103,7 +105,7 @@ static std::unique_ptr<FlutterDesktopEngineState> RunFlutterEngine(
     return reinterpret_cast<void*>(eglGetProcAddress(what));
   };
   config.open_gl.make_resource_current = [](void* user_data) -> bool {
-    auto host = static_cast<flutter::Win32FlutterWindow*>(user_data);
+    auto host = static_cast<flutter::FlutterWindowsView*>(user_data);
     return host->MakeResourceCurrent();
   };
 
@@ -178,7 +180,7 @@ static std::unique_ptr<FlutterDesktopEngineState> RunFlutterEngine(
   args.platform_message_callback =
       [](const FlutterPlatformMessage* engine_message,
          void* user_data) -> void {
-    auto window = reinterpret_cast<flutter::Win32FlutterWindow*>(user_data);
+    auto window = reinterpret_cast<flutter::FlutterWindowsView*>(user_data);
     return window->HandlePlatformMessage(engine_message);
   };
   args.custom_task_runners = &custom_task_runners;
@@ -188,7 +190,7 @@ static std::unique_ptr<FlutterDesktopEngineState> RunFlutterEngine(
 
   FLUTTER_API_SYMBOL(FlutterEngine) engine = nullptr;
   auto result =
-      FlutterEngineRun(FLUTTER_ENGINE_VERSION, &config, &args, window, &engine);
+      FlutterEngineRun(FLUTTER_ENGINE_VERSION, &config, &args, view, &engine);
   if (result != kSuccess || engine == nullptr) {
     std::cerr << "Failed to start Flutter engine: error " << result
               << std::endl;
@@ -202,8 +204,12 @@ FlutterDesktopViewControllerRef FlutterDesktopCreateViewController(
     int width,
     int height,
     const FlutterDesktopEngineProperties& engine_properties) {
+  std::unique_ptr<flutter::FlutterWindowBindingHandler> window_wrapper =
+      std::make_unique<flutter::Win32FlutterWindow>(width, height);
+
   FlutterDesktopViewControllerRef state =
-      flutter::Win32FlutterWindow::CreateWin32FlutterWindow(width, height);
+      flutter::FlutterWindowsView::CreateFlutterWindowsView(
+          std::move(window_wrapper));
 
   auto engine_state = RunFlutterEngine(state->view.get(), engine_properties);
 
@@ -261,8 +267,8 @@ FlutterDesktopViewRef FlutterDesktopGetView(
   return controller->view_wrapper.get();
 }
 
-HWND FlutterDesktopViewGetHWND(FlutterDesktopViewRef view) {
-  return view->window->GetWindowHandle();
+HWND FlutterDesktopViewGetHWND(FlutterDesktopViewRef view_ref) {
+  return view_ref->view->GetRenderTarget()->GetWindowHandle();
 }
 
 UINT FlutterDesktopGetDpiForHWND(HWND hwnd) {
@@ -316,7 +322,7 @@ void FlutterDesktopRegistrarSetDestructionHandler(
 
 FlutterDesktopViewRef FlutterDesktopRegistrarGetView(
     FlutterDesktopPluginRegistrarRef registrar) {
-  return registrar->window;
+  return registrar->view;
 }
 
 bool FlutterDesktopMessengerSendWithReply(FlutterDesktopMessengerRef messenger,