chore: remove calls to DeprecatedLayoutImmediately (#51183)

* chore: remove calls to DeprecatedLayoutImmediately

Replace the calls to `DeprecatedLayoutImmediately` that have test
coverage.

- The docked DevTools test added last week covers the three calls in IWCV.

- api-web-contents-view-spec covers the calls from NativeWindow{Views,Mac}.

There are a couple of remaining calls that don't have test coverage yet.
I'll get to them in a followup.

* test: handle both sync or microtask layout

* refactor: add a FlushPendingRootLayout() helper

shell/browser/native_window.cc

@@ -240,6 +240,13 @@ void NativeWindow::SetShape(const std::vector<gfx::Rect>& rects) {
   widget()->SetShape(std::make_unique<std::vector<gfx::Rect>>(rects));
 }
 
+void NativeWindow::FlushPendingRootLayout(views::View* view) {
+  view->InvalidateLayout();
+
+  if (views::Widget* widget = view->GetWidget())
+    widget->LayoutRootViewIfNecessary();
+}
+
 bool NativeWindow::IsClosed() const {
   return is_closed_;
 }

shell/browser/native_window.h

@@ -462,6 +462,7 @@ class NativeWindow : public views::WidgetDelegate {
   const views::Widget* GetWidget() const override;
 
   void set_content_view(views::View* view) { content_view_ = view; }
+  void FlushPendingRootLayout(views::View* view);
 
   static inline constexpr base::cstring_view kNativeWindowKey =
       "__ELECTRON_NATIVE_WINDOW__";

shell/browser/native_window_mac.mm

@@ -381,7 +381,7 @@ void NativeWindowMac::SetContentView(views::View* view) {
 
   root_view->AddChildViewRaw(content_view());
 
-  root_view->DeprecatedLayoutImmediately();
+  FlushPendingRootLayout(root_view);
 }
 
 void NativeWindowMac::Close() {

shell/browser/native_window_views.cc

@@ -533,7 +533,7 @@ void NativeWindowViews::SetContentView(views::View* view) {
   set_content_view(view);
   focused_view_ = view;
   root_view_.GetMainView()->AddChildViewRaw(content_view());
-  root_view_.GetMainView()->DeprecatedLayoutImmediately();
+  FlushPendingRootLayout(root_view_.GetMainView());
 }
 
 void NativeWindowViews::Close() {

shell/browser/ui/inspectable_web_contents_view.cc

@@ -23,6 +23,16 @@
 #include "ui/views/window/client_view.h"
 
 namespace electron {
+namespace {
+
+void FlushPendingRootLayout(views::View* view) {
+  view->InvalidateLayout();
+
+  if (views::Widget* widget = view->GetWidget())
+    widget->LayoutRootViewIfNecessary();
+}
+
+}  // namespace
 
 class DevToolsWindowDelegate : public views::ClientView,
                                public views::WidgetDelegate {
@@ -135,7 +145,7 @@ void InspectableWebContentsView::ShowDevTools(bool activate) {
     devtools_web_view_->SetWebContents(
         inspectable_web_contents_->GetDevToolsWebContents());
     devtools_web_view_->RequestFocus();
-    DeprecatedLayoutImmediately();
+    FlushPendingRootLayout(this);
   }
 }
 
@@ -173,7 +183,7 @@ void InspectableWebContentsView::CloseDevTools() {
   } else {
     devtools_web_view_->SetVisible(false);
     devtools_web_view_->SetWebContents(nullptr);
-    DeprecatedLayoutImmediately();
+    FlushPendingRootLayout(this);
   }
 }
 
@@ -223,7 +233,7 @@ void InspectableWebContentsView::SetIsDocked(bool docked, bool activate) {
 void InspectableWebContentsView::SetContentsResizingStrategy(
     const DevToolsContentsResizingStrategy& strategy) {
   strategy_.CopyFrom(strategy);
-  DeprecatedLayoutImmediately();
+  FlushPendingRootLayout(this);
 }
 
 void InspectableWebContentsView::SetTitle(const std::u16string& title) {