feat: replace BrowserView with WebContentsView (#35658)

shell/browser/ui/cocoa/delayed_native_view_host.mm

@@ -15,9 +15,13 @@ DelayedNativeViewHost::~DelayedNativeViewHost() = default;
 
 void DelayedNativeViewHost::ViewHierarchyChanged(
     const views::ViewHierarchyChangedDetails& details) {
-  NativeViewHost::ViewHierarchyChanged(details);
-  if (details.is_add && GetWidget())
-    Attach(native_view_);
+  // NativeViewHost doesn't expect to have children, so filter the
+  // ViewHierarchyChanged events before passing them on.
+  if (details.child == this) {
+    NativeViewHost::ViewHierarchyChanged(details);
+    if (details.is_add && GetWidget() && !native_view())
+      Attach(native_view_);
+  }
 }
 
 bool DelayedNativeViewHost::OnMousePressed(const ui::MouseEvent& ui_event) {

shell/browser/ui/cocoa/root_view_mac.h

@@ -22,7 +22,6 @@ class RootViewMac : public views::View {
   RootViewMac& operator=(const RootViewMac&) = delete;
 
   // views::View:
-  void Layout() override;
   gfx::Size GetMinimumSize() const override;
   gfx::Size GetMaximumSize() const override;
 

shell/browser/ui/cocoa/root_view_mac.mm

@@ -4,23 +4,20 @@
 
 #include "shell/browser/ui/cocoa/root_view_mac.h"
 
+#include <memory>
+
 #include "shell/browser/native_window.h"
+#include "ui/views/layout/fill_layout.h"
 
 namespace electron {
 
 RootViewMac::RootViewMac(NativeWindow* window) : window_(window) {
   set_owned_by_client();
+  SetLayoutManager(std::make_unique<views::FillLayout>());
 }
 
 RootViewMac::~RootViewMac() = default;
 
-void RootViewMac::Layout() {
-  if (!window_->content_view())  // Not ready yet.
-    return;
-
-  window_->content_view()->SetBoundsRect(gfx::Rect(gfx::Point(), size()));
-}
-
 gfx::Size RootViewMac::GetMinimumSize() const {
   return window_->GetMinimumSize();
 }

shell/browser/ui/views/frameless_view.cc

@@ -4,7 +4,6 @@
 
 #include "shell/browser/ui/views/frameless_view.h"
 
-#include "shell/browser/native_browser_view_views.h"
 #include "shell/browser/native_window_views.h"
 #include "shell/browser/ui/views/inspectable_web_contents_view_views.h"
 #include "ui/aura/window.h"