Add WidgetTest::GetAllWidgets() to find dialogs created by TestBrowserDialog.

chrome/browser/ui/test/test_browser_dialog.cc

Index: chrome/browser/ui/test/test_browser_dialog.cc
diff --git a/chrome/browser/ui/test/test_browser_dialog.cc b/chrome/browser/ui/test/test_browser_dialog.cc
index 5faa2fa206385a6c883b70d4f225e1dcb37158fa..75aff27f6ab391a12d30d0544041fe9b4b5f31e6 100644
--- a/chrome/browser/ui/test/test_browser_dialog.cc
+++ b/chrome/browser/ui/test/test_browser_dialog.cc
@@ -13,9 +13,14 @@
 #include "ui/base/test/material_design_controller_test_api.h"
 #include "ui/base/test/user_interactive_test_case.h"
 #include "ui/base/ui_base_switches.h"
+#include "ui/views/test/widget_test.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_observer.h"
 
+#if defined(OS_CHROMEOS)
+#include "ash/shell.h"  // nogncheck
+#endif
+
 namespace {
 
 // An automatic action for WidgetCloser to post to the RunLoop.
@@ -86,13 +91,22 @@ void TestBrowserDialog::RunDialog() {
   md_test_api.SetSecondaryUiMaterial(true);
 #endif
 
-  gfx::NativeView parent = platform_util::GetViewForWindow(DialogParent());
-  views::Widget::Widgets widgets_before;
-  views::Widget::GetAllChildWidgets(parent, &widgets_before);
+  views::Widget::Widgets widgets_before =
+      views::test::WidgetTest::GetAllWidgets();
+#if defined(OS_CHROMEOS)
+  // GetAllWidgets() uses AuraTestHelper to find the aura root window, but
+  // that's not used on browser_tests, so ask ash.
+  views::Widget::GetAllChildWidgets(ash::Shell::GetPrimaryRootWindow(),
+                                    &widgets_before);
+#endif  // OS_CHROMEOS
 
   ShowDialog(NameFromTestCase());
-  views::Widget::Widgets widgets_after;
-  views::Widget::GetAllChildWidgets(parent, &widgets_after);
+  views::Widget::Widgets widgets_after =
+      views::test::WidgetTest::GetAllWidgets();
+#if defined(OS_CHROMEOS)
+  views::Widget::GetAllChildWidgets(ash::Shell::GetPrimaryRootWindow(),
+                                    &widgets_after);
+#endif  // OS_CHROMEOS
 
   auto added = base::STLSetDifference<std::vector<views::Widget*>>(
       widgets_after, widgets_before);