Refactor FlutterEngine usage in Linux shell (#17363)

ci/licenses_golden/licenses_flutter

@@ -1162,8 +1162,15 @@ FILE: ../../../flutter/shell/platform/glfw/public/flutter_glfw.h
 FILE: ../../../flutter/shell/platform/glfw/text_input_plugin.cc
 FILE: ../../../flutter/shell/platform/glfw/text_input_plugin.h
 FILE: ../../../flutter/shell/platform/linux/fl_dart_project.cc
+FILE: ../../../flutter/shell/platform/linux/fl_engine.cc
+FILE: ../../../flutter/shell/platform/linux/fl_engine_private.h
+FILE: ../../../flutter/shell/platform/linux/fl_renderer.cc
+FILE: ../../../flutter/shell/platform/linux/fl_renderer.h
+FILE: ../../../flutter/shell/platform/linux/fl_renderer_x11.cc
+FILE: ../../../flutter/shell/platform/linux/fl_renderer_x11.h
 FILE: ../../../flutter/shell/platform/linux/fl_view.cc
 FILE: ../../../flutter/shell/platform/linux/public/flutter_linux/fl_dart_project.h
+FILE: ../../../flutter/shell/platform/linux/public/flutter_linux/fl_engine.h
 FILE: ../../../flutter/shell/platform/linux/public/flutter_linux/fl_view.h
 FILE: ../../../flutter/shell/platform/linux/public/flutter_linux/flutter_linux.h
 FILE: ../../../flutter/shell/platform/windows/angle_surface_manager.cc

shell/platform/linux/BUILD.gn

@@ -57,6 +57,9 @@ source_set("flutter_linux") {
 
   sources = [
     "fl_dart_project.cc",
+    "fl_engine.cc",
+    "fl_renderer.cc",
+    "fl_renderer_x11.cc",
     "fl_view.cc",
   ]
 

shell/platform/linux/fl_engine.cc

@@ -0,0 +1,159 @@
+// 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.
+
+#include "flutter/shell/platform/linux/public/flutter_linux/fl_engine.h"
+#include "flutter/shell/platform/linux/fl_engine_private.h"
+#include "flutter/shell/platform/linux/fl_renderer.h"
+
+#include <gmodule.h>
+
+struct _FlEngine {
+  GObject parent_instance;
+
+  FlDartProject* project;
+  FlRenderer* renderer;
+  FLUTTER_API_SYMBOL(FlutterEngine) engine;
+};
+
+G_DEFINE_QUARK(fl_engine_error_quark, fl_engine_error)
+
+G_DEFINE_TYPE(FlEngine, fl_engine, G_TYPE_OBJECT)
+
+// Callback from Flutter engine that are passed to the renderer
+
+static void* fl_engine_gl_proc_resolver(void* user_data, const char* name) {
+  FlEngine* self = static_cast<FlEngine*>(user_data);
+  return fl_renderer_get_proc_address(self->renderer, name);
+}
+
+static bool fl_engine_gl_make_current(void* user_data) {
+  FlEngine* self = static_cast<FlEngine*>(user_data);
+  g_autoptr(GError) error = nullptr;
+  gboolean result = fl_renderer_make_current(self->renderer, &error);
+  if (!result)
+    g_warning("%s", error->message);
+  return result;
+}
+
+static bool fl_engine_gl_clear_current(void* user_data) {
+  FlEngine* self = static_cast<FlEngine*>(user_data);
+  g_autoptr(GError) error = nullptr;
+  gboolean result = fl_renderer_clear_current(self->renderer, &error);
+  if (!result)
+    g_warning("%s", error->message);
+  return result;
+}
+
+static uint32_t fl_engine_gl_fbo_callback(void* user_data) {
+  FlEngine* self = static_cast<FlEngine*>(user_data);
+  return fl_renderer_get_fbo(self->renderer);
+}
+
+static bool fl_engine_gl_present(void* user_data) {
+  FlEngine* self = static_cast<FlEngine*>(user_data);
+  g_autoptr(GError) error = nullptr;
+  gboolean result = fl_renderer_present(self->renderer, &error);
+  if (!result)
+    g_warning("%s", error->message);
+  return result;
+}
+
+static void fl_engine_dispose(GObject* object) {
+  FlEngine* self = FL_ENGINE(object);
+
+  g_clear_object(&self->project);
+  g_clear_object(&self->renderer);
+
+  FlutterEngineShutdown(self->engine);
+
+  G_OBJECT_CLASS(fl_engine_parent_class)->dispose(object);
+}
+
+static void fl_engine_class_init(FlEngineClass* klass) {
+  G_OBJECT_CLASS(klass)->dispose = fl_engine_dispose;
+}
+
+static void fl_engine_init(FlEngine* self) {}
+
+FlEngine* fl_engine_new(FlDartProject* project, FlRenderer* renderer) {
+  g_return_val_if_fail(FL_IS_DART_PROJECT(project), nullptr);
+  g_return_val_if_fail(FL_IS_RENDERER(renderer), nullptr);
+
+  FlEngine* self =
+      static_cast<FlEngine*>(g_object_new(fl_engine_get_type(), nullptr));
+  self->project = static_cast<FlDartProject*>(g_object_ref(project));
+  self->renderer = static_cast<FlRenderer*>(g_object_ref(renderer));
+  return self;
+}
+
+gboolean fl_engine_start(FlEngine* self, GError** error) {
+  g_return_val_if_fail(FL_IS_ENGINE(self), FALSE);
+
+  if (!fl_renderer_start(self->renderer, error))
+    return FALSE;
+
+  FlutterRendererConfig config = {};
+  config.type = kOpenGL;
+  config.open_gl.struct_size = sizeof(FlutterOpenGLRendererConfig);
+  config.open_gl.gl_proc_resolver = fl_engine_gl_proc_resolver;
+  config.open_gl.make_current = fl_engine_gl_make_current;
+  config.open_gl.clear_current = fl_engine_gl_clear_current;
+  config.open_gl.fbo_callback = fl_engine_gl_fbo_callback;
+  config.open_gl.present = fl_engine_gl_present;
+
+  FlutterProjectArgs args = {};
+  args.struct_size = sizeof(FlutterProjectArgs);
+  args.assets_path = fl_dart_project_get_assets_path(self->project);
+  args.icu_data_path = fl_dart_project_get_icu_data_path(self->project);
+
+  FlutterEngineResult result = FlutterEngineInitialize(
+      FLUTTER_ENGINE_VERSION, &config, &args, self, &self->engine);
+  if (result != kSuccess) {
+    g_set_error(error, fl_engine_error_quark(), FL_ENGINE_ERROR_FAILED,
+                "Failed to initialize Flutter engine");
+    return FALSE;
+  }
+
+  result = FlutterEngineRunInitialized(self->engine);
+  if (result != kSuccess) {
+    g_set_error(error, fl_engine_error_quark(), FL_ENGINE_ERROR_FAILED,
+                "Failed to run Flutter engine");
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+void fl_engine_send_window_metrics_event(FlEngine* self,
+                                         size_t width,
+                                         size_t height,
+                                         double pixel_ratio) {
+  g_return_if_fail(FL_IS_ENGINE(self));
+
+  FlutterWindowMetricsEvent event = {};
+  event.struct_size = sizeof(FlutterWindowMetricsEvent);
+  event.width = width;
+  event.height = height;
+  event.pixel_ratio = pixel_ratio;
+  FlutterEngineSendWindowMetricsEvent(self->engine, &event);
+}
+
+void fl_engine_send_mouse_pointer_event(FlEngine* self,
+                                        FlutterPointerPhase phase,
+                                        size_t timestamp,
+                                        double x,
+                                        double y,
+                                        int64_t buttons) {
+  g_return_if_fail(FL_IS_ENGINE(self));
+
+  FlutterPointerEvent fl_event = {};
+  fl_event.struct_size = sizeof(fl_event);
+  fl_event.phase = phase;
+  fl_event.timestamp = timestamp;
+  fl_event.x = x;
+  fl_event.y = y;
+  fl_event.device_kind = kFlutterPointerDeviceKindMouse;
+  fl_event.buttons = buttons;
+  FlutterEngineSendPointerEvent(self->engine, &fl_event, 1);
+}

shell/platform/linux/fl_engine_private.h

@@ -0,0 +1,85 @@
+// 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_LINUX_FL_ENGINE_PRIVATE_H_
+#define FLUTTER_SHELL_PLATFORM_LINUX_FL_ENGINE_PRIVATE_H_
+
+#include <glib-object.h>
+
+#include "flutter/shell/platform/embedder/embedder.h"
+#include "flutter/shell/platform/linux/fl_renderer.h"
+#include "flutter/shell/platform/linux/public/flutter_linux/fl_dart_project.h"
+#include "flutter/shell/platform/linux/public/flutter_linux/fl_engine.h"
+
+G_BEGIN_DECLS
+
+/**
+ * FlEngineError:
+ * Errors for #FlEngine objects to set on failures.
+ */
+
+typedef enum {
+  FL_ENGINE_ERROR_FAILED,
+} FlEngineError;
+
+GQuark fl_engine_error_quark(void) G_GNUC_CONST;
+
+/**
+ * fl_engine_new:
+ * @project: a #FlDartProject
+ * @renderer: a #FlRenderer
+ *
+ * Creates a new Flutter engine.
+ *
+ * Returns: a #FlEngine
+ */
+FlEngine* fl_engine_new(FlDartProject* project, FlRenderer* renderer);
+
+/**
+ * fl_engine_start:
+ * @engine: a #FlEngine
+ * @error: (allow-none): #GError location to store the error occurring, or %NULL
+ * to ignore.
+ *
+ * Starts the Flutter engine.
+ *
+ * Returns: %TRUE on success
+ */
+gboolean fl_engine_start(FlEngine* engine, GError** error);
+
+/**
+ * fl_engine_send_window_metrics_event:
+ * @engine: a #FlEngine
+ * @width: width of the window in pixels.
+ * @height: height of the window in pixels.
+ * @pixel_ratio: scale factor for window.
+ *
+ * Sends a window metrics event to the engine.
+ */
+void fl_engine_send_window_metrics_event(FlEngine* engine,
+                                         size_t width,
+                                         size_t height,
+                                         double pixel_ratio);
+
+/**
+ * fl_engine_send_mouse_pointer_event:
+ * @engine: a #FlEngine
+ * @phase: mouse phase.
+ * @timestamp: time when event occurred in nanoseconds.
+ * @x: x location of mouse cursor.
+ * @y: y location of mouse cursor.
+ * @buttons: buttons that are pressed.
+ *
+ * Sends a mouse pointer event to the engine.
+ */
+void fl_engine_send_mouse_pointer_event(FlEngine* engine,
+                                        FlutterPointerPhase phase,
+                                        size_t timestamp,
+                                        double x,
+                                        double y,
+                                        int64_t buttons);
+
+G_END_DECLS
+
+#endif  // FLUTTER_SHELL_PLATFORM_LINUX_FL_ENGINE_PRIVATE_H_

shell/platform/linux/fl_renderer.cc

@@ -0,0 +1,139 @@
+// 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.
+
+#include "fl_renderer.h"
+
+#include "flutter/shell/platform/embedder/embedder.h"
+
+G_DEFINE_QUARK(fl_renderer_error_quark, fl_renderer_error)
+
+typedef struct {
+  EGLDisplay egl_display;
+  EGLSurface egl_surface;
+  EGLContext egl_context;
+} FlRendererPrivate;
+
+G_DEFINE_TYPE_WITH_PRIVATE(FlRenderer, fl_renderer, G_TYPE_OBJECT)
+
+// Default implementation for the start virtual method.
+// Provided so subclasses can chain up to here.
+static gboolean fl_renderer_real_start(FlRenderer* self, GError** error) {
+  FlRendererPrivate* priv =
+      static_cast<FlRendererPrivate*>(fl_renderer_get_instance_private(self));
+
+  // Note the use of EGL_DEFAULT_DISPLAY rather than sharing an existing display
+  // connection (e.g. an X11 connection from GTK). This is because this EGL
+  // display is going to be accessed by a thread from Flutter. In the case
+  // of GTK/X11 the display connection is not thread safe and this would cause
+  // a crash.
+  //
+  priv->egl_display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
+
+  if (!eglInitialize(priv->egl_display, nullptr, nullptr)) {
+    g_set_error(error, fl_renderer_error_quark(), FL_RENDERER_ERROR_FAILED,
+                "Failed to initialze EGL");
+    return FALSE;
+  }
+
+  EGLint attributes[] = {EGL_RENDERABLE_TYPE,
+                         EGL_OPENGL_ES2_BIT,
+                         EGL_RED_SIZE,
+                         8,
+                         EGL_GREEN_SIZE,
+                         8,
+                         EGL_BLUE_SIZE,
+                         8,
+                         EGL_ALPHA_SIZE,
+                         8,
+                         EGL_NONE};
+  EGLConfig egl_config;
+  EGLint n_config;
+  if (!eglChooseConfig(priv->egl_display, attributes, &egl_config, 1,
+                       &n_config)) {
+    g_set_error(error, fl_renderer_error_quark(), FL_RENDERER_ERROR_FAILED,
+                "Failed to choose EGL config");
+    return FALSE;
+  }
+  if (n_config == 0) {
+    g_set_error(error, fl_renderer_error_quark(), FL_RENDERER_ERROR_FAILED,
+                "Failed to find appropriate EGL config");
+    return FALSE;
+  }
+  if (!eglBindAPI(EGL_OPENGL_ES_API)) {
+    g_set_error(error, fl_renderer_error_quark(), FL_RENDERER_ERROR_FAILED,
+                "Failed to bind EGL OpenGL ES API");
+    return FALSE;
+  }
+
+  priv->egl_surface = FL_RENDERER_GET_CLASS(self)->create_surface(
+      self, priv->egl_display, egl_config);
+  EGLint context_attributes[] = {EGL_CONTEXT_CLIENT_VERSION, 2, EGL_NONE};
+  priv->egl_context = eglCreateContext(priv->egl_display, egl_config,
+                                       EGL_NO_CONTEXT, context_attributes);
+  EGLint value;
+  eglQueryContext(priv->egl_display, priv->egl_context,
+                  EGL_CONTEXT_CLIENT_VERSION, &value);
+
+  return TRUE;
+}
+
+static void fl_renderer_class_init(FlRendererClass* klass) {
+  klass->start = fl_renderer_real_start;
+}
+
+static void fl_renderer_init(FlRenderer* self) {}
+
+gboolean fl_renderer_start(FlRenderer* self, GError** error) {
+  return FL_RENDERER_GET_CLASS(self)->start(self, error);
+}
+
+void* fl_renderer_get_proc_address(FlRenderer* self, const char* name) {
+  return reinterpret_cast<void*>(eglGetProcAddress(name));
+}
+
+gboolean fl_renderer_make_current(FlRenderer* self, GError** error) {
+  FlRendererPrivate* priv =
+      static_cast<FlRendererPrivate*>(fl_renderer_get_instance_private(self));
+
+  if (!eglMakeCurrent(priv->egl_display, priv->egl_surface, priv->egl_surface,
+                      priv->egl_context)) {
+    g_set_error(error, fl_renderer_error_quark(), FL_RENDERER_ERROR_FAILED,
+                "Failed to make EGL context current");
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+gboolean fl_renderer_clear_current(FlRenderer* self, GError** error) {
+  FlRendererPrivate* priv =
+      static_cast<FlRendererPrivate*>(fl_renderer_get_instance_private(self));
+
+  if (!eglMakeCurrent(priv->egl_display, EGL_NO_SURFACE, EGL_NO_SURFACE,
+                      EGL_NO_CONTEXT)) {
+    g_set_error(error, fl_renderer_error_quark(), FL_RENDERER_ERROR_FAILED,
+                "Failed to clear EGL context");
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+guint32 fl_renderer_get_fbo(FlRenderer* self) {
+  // There is only one frame buffer object - always return that
+  return 0;
+}
+
+gboolean fl_renderer_present(FlRenderer* self, GError** error) {
+  FlRendererPrivate* priv =
+      static_cast<FlRendererPrivate*>(fl_renderer_get_instance_private(self));
+
+  if (!eglSwapBuffers(priv->egl_display, priv->egl_surface)) {
+    g_set_error(error, fl_renderer_error_quark(), FL_RENDERER_ERROR_FAILED,
+                "Failed to swap EGL buffers");
+    return FALSE;
+  }
+
+  return TRUE;
+}

shell/platform/linux/fl_renderer.h

@@ -0,0 +1,114 @@
+// 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_LINUX_FL_RENDERER_H_
+#define FLUTTER_SHELL_PLATFORM_LINUX_FL_RENDERER_H_
+
+#include <EGL/egl.h>
+
+#include <glib-object.h>
+
+#include "flutter/shell/platform/linux/public/flutter_linux/fl_dart_project.h"
+
+G_BEGIN_DECLS
+
+/**
+ * FlRendererError:
+ * Errors for #FlRenderer objects to set on failures.
+ */
+
+typedef enum {
+  FL_RENDERER_ERROR_FAILED,
+} FlRendererError;
+
+GQuark fl_renderer_error_quark(void) G_GNUC_CONST;
+
+G_DECLARE_DERIVABLE_TYPE(FlRenderer, fl_renderer, FL, RENDERER, GObject)
+
+/**
+ * FlRenderer:
+ *
+ * #FlRenderer is an abstract class that allows Flutter to draw pixels.
+ */
+
+struct _FlRendererClass {
+  GObjectClass parent_class;
+
+  // Virtual methods
+  gboolean (*start)(FlRenderer* renderer, GError** error);
+  EGLSurface (*create_surface)(FlRenderer* renderer,
+                               EGLDisplay display,
+                               EGLConfig config);
+};
+
+G_END_DECLS
+
+/**
+ * fl_renderer_start:
+ * @renderer: a #FlRenderer
+ * @error: (allow-none): #GError location to store the error occurring, or %NULL
+ * to ignore.
+ *
+ * Returns: %TRUE if successfully started.
+ */
+gboolean fl_renderer_start(FlRenderer* self, GError** error);
+
+/**
+ * fl_renderer_get_proc_address:
+ * @renderer: a #FlRenderer
+ * @name: a function name
+ *
+ * Gets the rendering API function that matches the given name.
+ *
+ * Returns: a function pointer
+ */
+void* fl_renderer_get_proc_address(FlRenderer* renderer, const char* name);
+
+/**
+ * fl_renderer_make_current:
+ * @renderer: a #FlRenderer
+ * @error: (allow-none): #GError location to store the error occurring, or %NULL
+ * to ignore.
+ *
+ * Makes the rendering context current.
+ *
+ * Returns %TRUE if successful
+ */
+gboolean fl_renderer_make_current(FlRenderer* renderer, GError** error);
+
+/**
+ * fl_renderer_clear_current:
+ * @renderer: a #FlRenderer
+ * @error: (allow-none): #GError location to store the error occurring, or %NULL
+ * to ignore.
+ *
+ * Clears the current rendering context.
+ *
+ * Returns %TRUE if successful
+ */
+gboolean fl_renderer_clear_current(FlRenderer* renderer, GError** error);
+
+/**
+ * fl_renderer_get_fbo:
+ * @renderer: a #FlRenderer
+ *
+ * Gets the frame buffer object to render to.
+ *
+ * Returns: a frame buffer object index
+ */
+guint32 fl_renderer_get_fbo(FlRenderer* renderer);
+
+/**
+ * fl_renderer_present:
+ * @renderer: a #FlRenderer
+ * @error: (allow-none): #GError location to store the error occurring, or %NULL
+ * to ignore.
+ *
+ * Presents the current frame.
+ *
+ * Returns %TRUE if successful
+ */
+gboolean fl_renderer_present(FlRenderer* renderer, GError** error);
+
+#endif  // FLUTTER_SHELL_PLATFORM_LINUX_FL_RENDERER_H_

shell/platform/linux/fl_renderer_x11.cc

@@ -0,0 +1,33 @@
+// 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.
+
+#include "fl_renderer_x11.h"
+
+struct _FlRendererX11 {
+  FlRenderer parent_instance;
+
+  Window xid;
+};
+
+G_DEFINE_TYPE(FlRendererX11, fl_renderer_x11, fl_renderer_get_type())
+
+static EGLSurface fl_renderer_x11_create_surface(FlRenderer* renderer,
+                                                 EGLDisplay display,
+                                                 EGLConfig config) {
+  FlRendererX11* self = FL_RENDERER_X11(renderer);
+  return eglCreateWindowSurface(display, config, self->xid, nullptr);
+}
+
+static void fl_renderer_x11_class_init(FlRendererX11Class* klass) {
+  FL_RENDERER_CLASS(klass)->create_surface = fl_renderer_x11_create_surface;
+}
+
+static void fl_renderer_x11_init(FlRendererX11* self) {}
+
+FlRendererX11* fl_renderer_x11_new(Window xid) {
+  FlRendererX11* self = static_cast<FlRendererX11*>(
+      g_object_new(fl_renderer_x11_get_type(), nullptr));
+  self->xid = xid;
+  return self;
+}

shell/platform/linux/fl_renderer_x11.h

@@ -0,0 +1,39 @@
+// 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_LINUX_FL_RENDERER_X11_H_
+#define FLUTTER_SHELL_PLATFORM_LINUX_FL_RENDERER_X11_H_
+
+#include <gdk/gdkx.h>
+
+#include "flutter/shell/platform/linux/fl_renderer.h"
+
+G_BEGIN_DECLS
+
+G_DECLARE_FINAL_TYPE(FlRendererX11,
+                     fl_renderer_x11,
+                     FL,
+                     RENDERER_X11,
+                     FlRenderer)
+
+/**
+ * FlRendererX11:
+ *
+ * #FlRendererX11 is an implementation of a #FlRenderer that renders to X11
+ * windows.
+ */
+
+/**
+ * fl_renderer_x11_new:
+ * @xid: The X window to render to.
+ *
+ * Create an object that allows Flutter to render to X11 windows.
+ *
+ * Returns: a #FlRendererX11
+ */
+FlRendererX11* fl_renderer_x11_new(Window xid);
+
+G_END_DECLS
+
+#endif  // FLUTTER_SHELL_PLATFORM_LINUX_FL_RENDERER_X11_H_

shell/platform/linux/fl_view.cc

@@ -4,22 +4,19 @@
 
 #include "flutter/shell/platform/linux/public/flutter_linux/fl_view.h"
 
-#include <EGL/egl.h>
-#include <EGL/eglext.h>
-#include <GLES2/gl2.h>
+#include "flutter/shell/platform/linux/fl_engine_private.h"
+#include "flutter/shell/platform/linux/fl_renderer_x11.h"
+#include "flutter/shell/platform/linux/public/flutter_linux/fl_engine.h"
+
 #include <gdk/gdkx.h>
 
-#include "flutter/shell/platform/embedder/embedder.h"
+#define NSEC_PER_MSEC 1000000
 
 struct _FlView {
   GtkWidget parent_instance;
 
-  EGLDisplay egl_display;
-  EGLSurface egl_surface;
-  EGLContext egl_context;
-
-  FlDartProject* flutter_project;
-  FLUTTER_API_SYMBOL(FlutterEngine) flutter_engine;
+  FlDartProject* project;
+  FlEngine* engine;
   int64_t button_state;
 };
 
@@ -27,139 +24,9 @@ enum { PROP_FLUTTER_PROJECT = 1, PROP_LAST };
 
 G_DEFINE_TYPE(FlView, fl_view, GTK_TYPE_WIDGET)
 
-static gboolean initialize_egl(FlView* self) {
-  /* Note that we don't provide the XDisplay from GTK, this would make both
-   * GTK and EGL share the same X connection and this would crash when used by
-   * a Flutter thread. So the EGL display and GTK both have separate
-   * connections.
-   */
-  self->egl_display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
-
-  EGLint egl_major, egl_minor;
-  if (!eglInitialize(self->egl_display, &egl_major, &egl_minor)) {
-    g_warning("Failed to initialze EGL");
-    return FALSE;
-  }
-  // TODO(robert-ancell): It would probably be useful to store the EGL version
-  // for debugging purposes
-
-  EGLint attributes[] = {EGL_RENDERABLE_TYPE,
-                         EGL_OPENGL_ES2_BIT,
-                         EGL_RED_SIZE,
-                         8,
-                         EGL_GREEN_SIZE,
-                         8,
-                         EGL_BLUE_SIZE,
-                         8,
-                         EGL_ALPHA_SIZE,
-                         8,
-                         EGL_NONE};
-  EGLConfig egl_config;
-  EGLint n_config;
-  if (!eglChooseConfig(self->egl_display, attributes, &egl_config, 1,
-                       &n_config)) {
-    g_warning("Failed to choose EGL config");
-    return FALSE;
-  }
-  if (n_config == 0) {
-    g_warning("Failed to find appropriate EGL config");
-    return FALSE;
-  }
-  if (!eglBindAPI(EGL_OPENGL_ES_API)) {
-    g_warning("Failed to bind EGL OpenGL ES API");
-    return FALSE;
-  }
-
-  Window xid = gdk_x11_window_get_xid(gtk_widget_get_window(GTK_WIDGET(self)));
-  self->egl_surface =
-      eglCreateWindowSurface(self->egl_display, egl_config, xid, nullptr);
-  EGLint context_attributes[] = {EGL_CONTEXT_CLIENT_VERSION, 2, EGL_NONE};
-  self->egl_context = eglCreateContext(self->egl_display, egl_config,
-                                       EGL_NO_CONTEXT, context_attributes);
-  EGLint value;
-  eglQueryContext(self->egl_display, self->egl_context,
-                  EGL_CONTEXT_CLIENT_VERSION, &value);
-
-  return TRUE;
-}
-
-static void* fl_view_gl_proc_resolver(void* user_data, const char* name) {
-  return reinterpret_cast<void*>(eglGetProcAddress(name));
-}
-
-static bool fl_view_gl_make_current(void* user_data) {
-  FlView* self = static_cast<FlView*>(user_data);
-
-  if (!eglMakeCurrent(self->egl_display, self->egl_surface, self->egl_surface,
-                      self->egl_context))
-    g_warning("Failed to make EGL context current");
-
-  return true;
-}
-
-static bool fl_view_gl_clear_current(void* user_data) {
-  FlView* self = static_cast<FlView*>(user_data);
-
-  if (!eglMakeCurrent(self->egl_display, EGL_NO_SURFACE, EGL_NO_SURFACE,
-                      EGL_NO_CONTEXT))
-    g_warning("Failed to make EGL context current");
-
-  return true;
-}
-
-static uint32_t fl_view_gl_fbo_callback(void* user_data) {
-  /* There is only one frame buffer object - always return that */
-  return 0;
-}
-
-static bool fl_view_gl_present(void* user_data) {
-  FlView* self = static_cast<FlView*>(user_data);
-
-  if (!eglSwapBuffers(self->egl_display, self->egl_surface))
-    g_warning("Failed to swap EGL buffers");
-
-  return true;
-}
-
-static gboolean run_flutter_engine(FlView* self) {
-  FlutterRendererConfig config = {};
-  config.type = kOpenGL;
-  config.open_gl.struct_size = sizeof(FlutterOpenGLRendererConfig);
-  config.open_gl.gl_proc_resolver = fl_view_gl_proc_resolver;
-  config.open_gl.make_current = fl_view_gl_make_current;
-  config.open_gl.clear_current = fl_view_gl_clear_current;
-  config.open_gl.fbo_callback = fl_view_gl_fbo_callback;
-  config.open_gl.present = fl_view_gl_present;
-
-  g_autofree gchar* assets_path =
-      fl_dart_project_get_assets_path(self->flutter_project);
-  g_autofree gchar* icu_data_path =
-      fl_dart_project_get_icu_data_path(self->flutter_project);
-
-  FlutterProjectArgs args = {};
-  args.struct_size = sizeof(FlutterProjectArgs);
-  args.assets_path = assets_path;
-  args.icu_data_path = icu_data_path;
-
-  FlutterEngineResult result = FlutterEngineInitialize(
-      FLUTTER_ENGINE_VERSION, &config, &args, self, &self->flutter_engine);
-  if (result != kSuccess)
-    return FALSE;
-
-  result = FlutterEngineRunInitialized(self->flutter_engine);
-  if (result != kSuccess)
-    return FALSE;
-
-  return TRUE;
-}
-
-/* Convert a GDK button event into a Flutter event and send to the engine */
+// Convert a GDK button event into a Flutter event and send to the engine
 static gboolean fl_view_send_pointer_button_event(FlView* self,
                                                   GdkEventButton* event) {
-  FlutterPointerEvent fl_event = {};
-  fl_event.struct_size = sizeof(fl_event);
-  fl_event.timestamp = event->time * 1000;
-
   int64_t button;
   switch (event->button) {
     case 1:
@@ -175,31 +42,29 @@ static gboolean fl_view_send_pointer_button_event(FlView* self,
       return FALSE;
   }
   int old_button_state = self->button_state;
+  FlutterPointerPhase phase;
   if (event->type == GDK_BUTTON_PRESS) {
     // Drop the event if Flutter already thinks the button is down
     if ((self->button_state & button) != 0)
       return FALSE;
     self->button_state ^= button;
 
-    fl_event.phase = old_button_state == 0 ? kDown : kMove;
+    phase = old_button_state == 0 ? kDown : kMove;
   } else if (event->type == GDK_BUTTON_RELEASE) {
     // Drop the event if Flutter already thinks the button is up
     if ((self->button_state & button) == 0)
       return FALSE;
     self->button_state ^= button;
 
-    fl_event.phase = self->button_state == 0 ? kUp : kMove;
+    phase = self->button_state == 0 ? kUp : kMove;
   }
 
-  if (self->flutter_engine == nullptr)
+  if (self->engine == nullptr)
     return FALSE;
 
-  fl_event.x = event->x;
-  fl_event.y = event->y;
-  fl_event.device_kind = kFlutterPointerDeviceKindMouse;
-  fl_event.buttons = self->button_state;
-  FlutterEngineSendPointerEvent(self->flutter_engine, &fl_event, 1);
-
+  fl_engine_send_mouse_pointer_event(self->engine, phase,
+                                     event->time * NSEC_PER_MSEC, event->x,
+                                     event->y, self->button_state);
   return TRUE;
 }
 
@@ -211,7 +76,7 @@ static void fl_view_set_property(GObject* object,
 
   switch (prop_id) {
     case PROP_FLUTTER_PROJECT:
-      g_set_object(&self->flutter_project,
+      g_set_object(&self->project,
                    static_cast<FlDartProject*>(g_value_get_object(value)));
       break;
     default:
@@ -228,7 +93,7 @@ static void fl_view_get_property(GObject* object,
 
   switch (prop_id) {
     case PROP_FLUTTER_PROJECT:
-      g_value_set_object(value, self->flutter_project);
+      g_value_set_object(value, self->project);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
@@ -239,17 +104,8 @@ static void fl_view_get_property(GObject* object,
 static void fl_view_dispose(GObject* object) {
   FlView* self = FL_VIEW(object);
 
-  FlutterEngineDeinitialize(self->flutter_engine);
-  FlutterEngineShutdown(self->flutter_engine);
-
-  if (!eglDestroyContext(self->egl_display, self->egl_context))
-    g_warning("Failed to destroy EGL context");
-  if (!eglDestroySurface(self->egl_display, self->egl_surface))
-    g_warning("Failed to destroy EGL surface");
-  if (!eglTerminate(self->egl_display))
-    g_warning("Failed to terminate EGL display");
-
-  g_clear_object(&self->flutter_project);
+  g_clear_object(&self->project);
+  g_clear_object(&self->engine);
 
   G_OBJECT_CLASS(fl_view_parent_class)->dispose(object);
 }
@@ -282,8 +138,12 @@ static void fl_view_realize(GtkWidget* widget) {
   gtk_widget_register_window(widget, window);
   gtk_widget_set_window(widget, window);
 
-  if (initialize_egl(self))
-    run_flutter_engine(self);
+  Window xid = gdk_x11_window_get_xid(gtk_widget_get_window(GTK_WIDGET(self)));
+  g_autoptr(FlRendererX11) renderer = fl_renderer_x11_new(xid);
+  self->engine = fl_engine_new(self->project, FL_RENDERER(renderer));
+  g_autoptr(GError) error = nullptr;
+  if (!fl_engine_start(self->engine, &error))
+    g_printerr("Failed to start Flutter engine: %s", error->message);
 }
 
 static void fl_view_size_allocate(GtkWidget* widget,
@@ -297,13 +157,9 @@ static void fl_view_size_allocate(GtkWidget* widget,
                            allocation->y, allocation->width,
                            allocation->height);
 
-  FlutterWindowMetricsEvent event = {};
-  event.struct_size = sizeof(FlutterWindowMetricsEvent);
-  event.width = allocation->width;
-  event.height = allocation->height;
-  event.pixel_ratio =
-      1;  // TODO(robert-ancell): This won't work on hidpi displays
-  FlutterEngineSendWindowMetricsEvent(self->flutter_engine, &event);
+  // TODO(robert-ancell): This pixel ratio won't work on hidpi displays
+  fl_engine_send_window_metrics_event(self->engine, allocation->width,
+                                      allocation->height, 1);
 }
 
 static gboolean fl_view_button_press_event(GtkWidget* widget,
@@ -329,18 +185,12 @@ static gboolean fl_view_motion_notify_event(GtkWidget* widget,
                                             GdkEventMotion* event) {
   FlView* self = FL_VIEW(widget);
 
-  if (self->flutter_engine == nullptr)
+  if (self->engine == nullptr)
     return FALSE;
 
-  FlutterPointerEvent fl_event = {};
-  fl_event.struct_size = sizeof(fl_event);
-  fl_event.timestamp = event->time * 1000;
-  fl_event.phase = self->button_state != 0 ? kMove : kHover;
-  fl_event.x = event->x;
-  fl_event.y = event->y;
-  fl_event.device_kind = kFlutterPointerDeviceKindMouse;
-  fl_event.buttons = self->button_state;
-  FlutterEngineSendPointerEvent(self->flutter_engine, &fl_event, 1);
+  fl_engine_send_mouse_pointer_event(
+      self->engine, self->button_state != 0 ? kMove : kHover,
+      event->time * NSEC_PER_MSEC, event->x, event->y, self->button_state);
 
   return TRUE;
 }
@@ -370,3 +220,8 @@ G_MODULE_EXPORT FlView* fl_view_new(FlDartProject* project) {
   return static_cast<FlView*>(
       g_object_new(fl_view_get_type(), "flutter-project", project, nullptr));
 }
+
+G_MODULE_EXPORT FlEngine* fl_view_get_engine(FlView* view) {
+  g_return_val_if_fail(FL_IS_VIEW(view), nullptr);
+  return view->engine;
+}

shell/platform/linux/public/flutter_linux/fl_engine.h

@@ -0,0 +1,28 @@
+// 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_LINUX_FL_ENGINE_H_
+#define FLUTTER_SHELL_PLATFORM_LINUX_FL_ENGINE_H_
+
+#if !defined(__FLUTTER_LINUX_INSIDE__) && !defined(FLUTTER_LINUX_COMPILATION)
+#error "Only <flutter_linux/flutter_linux.h> can be included directly."
+#endif
+
+#include <glib-object.h>
+
+#include "fl_dart_project.h"
+
+G_BEGIN_DECLS
+
+G_DECLARE_FINAL_TYPE(FlEngine, fl_engine, FL, ENGINE, GObject)
+
+/**
+ * FlEngine:
+ *
+ * #FlEngine is an object that contains a running Flutter engine.
+ */
+
+G_END_DECLS
+
+#endif  // FLUTTER_SHELL_PLATFORM_LINUX_FL_ENGINE_H_

shell/platform/linux/public/flutter_linux/fl_view.h

@@ -12,6 +12,7 @@
 #include <gtk/gtk.h>
 
 #include "fl_dart_project.h"
+#include "fl_engine.h"
 
 G_BEGIN_DECLS
 
@@ -33,6 +34,16 @@ G_DECLARE_FINAL_TYPE(FlView, fl_view, FL, VIEW, GtkWidget)
  */
 FlView* fl_view_new(FlDartProject* project);
 
+/**
+ * fl_view_get_engine:
+ * @view: a #FlView
+ *
+ * Gets the engine being rendered in the view.
+ *
+ * Returns: a #FlEngine
+ */
+FlEngine* fl_view_get_engine(FlView* view);
+
 G_END_DECLS
 
 #endif  // FLUTTER_SHELL_PLATFORM_LINUX_FL_VIEW_H_

shell/platform/linux/public/flutter_linux/flutter_linux.h

@@ -8,6 +8,7 @@
 #define __FLUTTER_LINUX_INSIDE__
 
 #include <flutter_linux/fl_dart_project.h>
+#include <flutter_linux/fl_engine.h>
 #include <flutter_linux/fl_view.h>
 
 #undef __FLUTTER_LINUX_INSIDE__