Move window state update to window realize callback (#47713)

## Description

This moves the state update to only happen on realizing the window instead of at initialization time, based on [the comment from](flutter/flutter#137262 (comment)) @robert-ancell .

## Related Issues
 - flutter/flutter#137262

## Tests
 - I tried to add tests, but it doesn't seem possible to create a view without an actual display connected (and making a mock of it defeats the purpose of the test). I'm happy to be proven wrong, though.

Author: gspencergoog

ci/licenses_golden/licenses_flutter

@@ -5053,6 +5053,7 @@ ORIGIN: ../../../flutter/shell/platform/linux/fl_view_accessible.cc + ../../../f
 ORIGIN: ../../../flutter/shell/platform/linux/fl_view_accessible.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/linux/fl_view_accessible_test.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/linux/fl_view_private.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/shell/platform/linux/fl_view_test.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/linux/key_mapping.g.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/linux/key_mapping.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/linux/public/flutter_linux/fl_basic_message_channel.h + ../../../flutter/LICENSE
@@ -7835,6 +7836,7 @@ FILE: ../../../flutter/shell/platform/linux/fl_view_accessible.cc
 FILE: ../../../flutter/shell/platform/linux/fl_view_accessible.h
 FILE: ../../../flutter/shell/platform/linux/fl_view_accessible_test.cc
 FILE: ../../../flutter/shell/platform/linux/fl_view_private.h
+FILE: ../../../flutter/shell/platform/linux/fl_view_test.cc
 FILE: ../../../flutter/shell/platform/linux/key_mapping.g.cc
 FILE: ../../../flutter/shell/platform/linux/key_mapping.h
 FILE: ../../../flutter/shell/platform/linux/public/flutter_linux/fl_basic_message_channel.h

shell/platform/linux/BUILD.gn

@@ -227,7 +227,10 @@ executable("flutter_linux_unittests") {
     "fl_texture_registrar_test.cc",
     "fl_value_test.cc",
     "fl_view_accessible_test.cc",
+    "fl_view_test.cc",
     "testing/fl_test.cc",
+    "testing/fl_test_gtk_logs.cc",
+    "testing/fl_test_gtk_logs.h",
     "testing/mock_binary_messenger.cc",
     "testing/mock_binary_messenger_response_handle.cc",
     "testing/mock_engine.cc",

shell/platform/linux/fl_view.cc

@@ -247,8 +247,6 @@ static void on_pre_engine_restart_cb(FlEngine* engine, gpointer user_data) {
   g_clear_object(&self->scrolling_manager);
   init_keyboard(self);
   init_scrolling(self);
-  self->window_state =
-      gdk_window_get_state(gtk_widget_get_window(GTK_WIDGET(self)));
 }
 
 // Implements FlPluginRegistry::get_registrar_for_plugin.
@@ -556,6 +554,8 @@ static void realize_cb(GtkWidget* widget) {
   self->window_state_cb_id =
       g_signal_connect(toplevel_window, "window-state-event",
                        G_CALLBACK(window_state_event_cb), self);
+  self->window_state =
+      gdk_window_get_state(gtk_widget_get_window(toplevel_window));
 
   g_signal_connect(toplevel_window, "delete-event",
                    G_CALLBACK(window_delete_event_cb), self);
@@ -760,8 +760,6 @@ static void fl_view_class_init(FlViewClass* klass) {
 
 static void fl_view_init(FlView* self) {
   gtk_widget_set_can_focus(GTK_WIDGET(self), TRUE);
-  self->window_state = gdk_window_get_state(
-      gtk_widget_get_window(gtk_widget_get_toplevel(GTK_WIDGET(self))));
 }
 
 G_MODULE_EXPORT FlView* fl_view_new(FlDartProject* project) {

shell/platform/linux/fl_view_test.cc

@@ -0,0 +1,20 @@
+// 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_view.h"
+#include "flutter/shell/platform/linux/testing/fl_test_gtk_logs.h"
+
+#include "gtest/gtest.h"
+
+TEST(FlViewTest, StateUpdateDoesNotHappenInInit) {
+  flutter::testing::fl_ensure_gtk_init();
+  g_autoptr(FlDartProject) project = fl_dart_project_new();
+  g_autoptr(FlView) view = fl_view_new(project);
+  // Check that creating a view doesn't try to query the window state in
+  // initialization, causing a critical log to be issued.
+  EXPECT_EQ(
+      flutter::testing::fl_get_received_gtk_log_levels() & G_LOG_LEVEL_CRITICAL,
+      (GLogLevelFlags)0x0);
+  g_object_ref_sink(view);
+}

shell/platform/linux/testing/fl_test_gtk_logs.cc

@@ -0,0 +1,54 @@
+// 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_test_gtk_logs.h"
+#include "gtest/gtest.h"
+
+namespace flutter {
+namespace testing {
+
+namespace {
+
+bool gtk_initialized = false;
+GLogWriterFunc log_writer_cb = nullptr;
+GLogLevelFlags fl_received_log_levels = (GLogLevelFlags)0x0;
+
+GLogWriterOutput log_writer(GLogLevelFlags log_level,
+                            const GLogField* fields,
+                            gsize n_fields,
+                            gpointer user_data) {
+  fl_received_log_levels = (GLogLevelFlags)(log_level | fl_received_log_levels);
+  if (log_writer_cb == nullptr) {
+    return g_log_writer_default(log_level, fields, n_fields, user_data);
+  }
+  GLogWriterOutput result =
+      log_writer_cb(log_level, fields, n_fields, user_data);
+  if (result != G_LOG_WRITER_HANDLED) {
+    return g_log_writer_default(log_level, fields, n_fields, user_data);
+  }
+  return result;
+}
+
+}  // namespace
+
+void fl_ensure_gtk_init(GLogWriterFunc writer) {
+  if (!gtk_initialized) {
+    gtk_init(0, nullptr);
+    g_log_set_writer_func(log_writer, nullptr, nullptr);
+    gtk_initialized = true;
+  }
+  fl_reset_received_gtk_log_levels();
+  log_writer_cb = writer;
+}
+
+void fl_reset_received_gtk_log_levels() {
+  fl_received_log_levels = (GLogLevelFlags)0x0;
+}
+
+GLogLevelFlags fl_get_received_gtk_log_levels() {
+  return fl_received_log_levels;
+}
+
+}  // namespace testing
+}  // namespace flutter

shell/platform/linux/testing/fl_test_gtk_logs.h

@@ -0,0 +1,49 @@
+// 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_TESTING_TEST_GTK_LOGS_H_
+#define FLUTTER_TESTING_TEST_GTK_LOGS_H_
+
+#include <gtk/gtk.h>
+
+namespace flutter {
+namespace testing {
+
+/**
+ * Ensures that GTK has been initialized. If GTK has not been initialized, it
+ * will be initialized using `gtk_init()`. It will also set the GTK log writer
+ * function to monitor the log output, recording the log levels that have been
+ * received in a bitfield accessible via {@link fl_get_received_gtk_log_levels}
+ *
+ * To retrieve the bitfield of recorded log levels, use
+ * `fl_get_received_gtk_log_levels()`.
+ *
+ * @param[in] writer The custom log writer function to use. If `nullptr`, or it
+ *      returns G_LOG_WRITER_UNHANDLED, the default log writer function will be
+ *      called.
+ *
+ * @brief Ensures that GTK has been initialized and starts monitoring logs.
+ */
+void fl_ensure_gtk_init(GLogWriterFunc writer = nullptr);
+
+/**
+ * Resets the recorded GTK log levels to zero.
+ *
+ * @brief Resets the recorded log levels.
+ */
+void fl_reset_received_gtk_log_levels();
+
+/**
+ * Returns a bitfield containing the GTK log levels that have been seen since
+ * the last time they were reset.
+ *
+ * @brief Returns the recorded log levels.
+ *
+ * @return A `GLogLevelFlags` bitfield representing the recorded log levels.
+ */
+GLogLevelFlags fl_get_received_gtk_log_levels();
+
+}  // namespace testing
+}  // namespace flutter
+#endif  // FLUTTER_TESTING_TEST_GTK_LOGS_H_

testing/BUILD.gn

@@ -51,6 +51,11 @@ source_set("testing") {
 
   sources = [ "run_all_unittests.cc" ]
 
+  if (is_linux) {
+    # So that we can call gtk_init in main().
+    configs += [ "//flutter/shell/platform/linux/config:gtk" ]
+  }
+
   public_deps = [ ":testing_lib" ]
   public_configs = [ ":dynamic_symbols" ]
 }

testing/run_tests.py

@@ -463,16 +463,23 @@ def make_test(name, flags=None, extra_env=None):
         make_test('flow_unittests', flags=repeat_flags + flow_flags),
     ]
 
-  for test, flags, extra_env in unittests:
-    run_engine_executable(
-        build_dir,
-        test,
-        executable_filter,
-        flags,
-        coverage=coverage,
-        extra_env=extra_env,
-        gtest=True
-    )
+  build_name = os.path.basename(build_dir)
+  try:
+    if is_linux():
+      xvfb.start_virtual_x(build_name, build_dir)
+    for test, flags, extra_env in unittests:
+      run_engine_executable(
+          build_dir,
+          test,
+          executable_filter,
+          flags,
+          coverage=coverage,
+          extra_env=extra_env,
+          gtest=True
+      )
+  finally:
+    if is_linux():
+      xvfb.stop_virtual_x(build_name)
 
   if is_mac():
     # flutter_desktop_darwin_unittests uses global state that isn't handled