chrome: Standardize fullscreen transition behavor/callbacks (fixes #3571)

Use the same code path for all fullscreen transitions so that Chrome UI updates
correctly. All user-initiated fullscreen transitions now result in
CefWindowDelegate::OnWindowFullscreenTransition callbacks.

libcef/browser/views/browser_view_impl.cc

@@ -141,10 +141,7 @@ bool CefBrowserViewImpl::HandleKeyboardEvent(
   }
 
   // Give the CefWindowDelegate a chance to handle the event.
-  CefRefPtr<CefWindow> window =
-      view_util::GetWindowFor(root_view()->GetWidget());
-  CefWindowImpl* window_impl = static_cast<CefWindowImpl*>(window.get());
-  if (window_impl) {
+  if (auto* window_impl = cef_window()) {
     CefKeyEvent cef_event;
     if (browser_util::GetCefKeyEvent(event, cef_event) &&
         window_impl->OnKeyEvent(cef_event)) {
@@ -319,6 +316,12 @@ ChromeBrowserView* CefBrowserViewImpl::chrome_browser_view() const {
   return static_cast<ChromeBrowserView*>(root_view());
 }
 
+CefWindowImpl* CefBrowserViewImpl::cef_window() const {
+  CefRefPtr<CefWindow> window =
+      view_util::GetWindowFor(root_view()->GetWidget());
+  return static_cast<CefWindowImpl*>(window.get());
+}
+
 bool CefBrowserViewImpl::HandleAccelerator(
     const content::NativeWebKeyboardEvent& event,
     views::FocusManager* focus_manager) {

libcef/browser/views/browser_view_impl.h

@@ -18,6 +18,7 @@
 #include "ui/views/controls/webview/unhandled_keyboard_event_handler.h"
 
 class CefBrowserHostBase;
+class CefWindowImpl;
 class ChromeBrowserView;
 
 class CefBrowserViewImpl
@@ -83,6 +84,9 @@ class CefBrowserViewImpl
   // Return the CEF specialization of BrowserView.
   ChromeBrowserView* chrome_browser_view() const;
 
+  // Return the CefWindowImpl hosting this object.
+  CefWindowImpl* cef_window() const;
+
  private:
   // Create a new implementation object.
   // Always call Initialize() after creation.

libcef/browser/views/native_widget_mac.h

@@ -48,6 +48,9 @@ class CefNativeWidgetMac : public views::NativeWidgetMac {
   const CefRefPtr<CefWindow> window_;
   CefWindowDelegate* const window_delegate_;
 
+  // Returns true if the CefWindow is fully initialized.
+  bool IsCefWindowInitialized() const;
+
   BrowserView* browser_view_ = nullptr;
 };
 

libcef/browser/views/native_widget_mac.mm

@@ -7,6 +7,7 @@
 #include "include/views/cef_window.h"
 #include "include/views/cef_window_delegate.h"
 #include "libcef/browser/views/ns_window.h"
+#include "libcef/browser/views/window_impl.h"
 
 #include "chrome/browser/apps/app_shim/app_shim_host_mac.h"
 #include "chrome/browser/apps/app_shim/app_shim_manager_mac.h"
@@ -118,12 +119,16 @@ void CefNativeWidgetMac::GetWindowFrameTitlebarHeight(
 
 void CefNativeWidgetMac::OnWindowFullscreenTransitionStart() {
   views::NativeWidgetMac::OnWindowFullscreenTransitionStart();
-  window_delegate_->OnWindowFullscreenTransition(window_, false);
+  if (IsCefWindowInitialized()) {
+    window_delegate_->OnWindowFullscreenTransition(window_, false);
+  }
 }
 
 void CefNativeWidgetMac::OnWindowFullscreenTransitionComplete() {
   views::NativeWidgetMac::OnWindowFullscreenTransitionComplete();
-  window_delegate_->OnWindowFullscreenTransition(window_, true);
+  if (IsCefWindowInitialized()) {
+    window_delegate_->OnWindowFullscreenTransition(window_, true);
+  }
 }
 
 void CefNativeWidgetMac::OnWindowInitialized() {
@@ -142,3 +147,7 @@ void CefNativeWidgetMac::OnWindowInitialized() {
     }
   }
 }
+
+bool CefNativeWidgetMac::IsCefWindowInitialized() const {
+  return static_cast<CefWindowImpl*>(window_.get())->initialized();
+}

libcef/browser/views/window_impl.cc

@@ -5,6 +5,7 @@
 #include "libcef/browser/views/window_impl.h"
 
 #include "libcef/browser/browser_util.h"
+#include "libcef/browser/chrome/views/chrome_browser_frame.h"
 #include "libcef/browser/thread_util.h"
 #include "libcef/browser/views/browser_view_impl.h"
 #include "libcef/browser/views/display_impl.h"
@@ -12,6 +13,7 @@
 #include "libcef/browser/views/layout_util.h"
 #include "libcef/browser/views/view_util.h"
 #include "libcef/browser/views/window_view.h"
+#include "libcef/features/runtime.h"
 
 #include "base/i18n/rtl.h"
 #include "components/constrained_window/constrained_window_views.h"
@@ -116,9 +118,6 @@ CefRefPtr<CefWindowImpl> CefWindowImpl::Create(
   CefRefPtr<CefWindowImpl> window = new CefWindowImpl(delegate);
   window->Initialize();
   window->CreateWidget(parent_widget);
-  if (delegate) {
-    delegate->OnWindowCreated(window.get());
-  }
   return window;
 }
 
@@ -253,7 +252,29 @@ void CefWindowImpl::Restore() {
 void CefWindowImpl::SetFullscreen(bool fullscreen) {
   CEF_REQUIRE_VALID_RETURN_VOID();
   if (widget_ && fullscreen != widget_->IsFullscreen()) {
+    if (cef::IsChromeRuntimeEnabled()) {
+      // If a BrowserView exists, toggle fullscreen mode via the Chrome command
+      // for consistent behavior.
+      auto* browser_frame = static_cast<ChromeBrowserFrame*>(widget_);
+      if (browser_frame->browser_view()) {
+        browser_frame->ToggleFullscreenMode();
+        return;
+      }
+    }
+
+    // Call the Widget method directly with Alloy runtime, or Chrome runtime
+    // when no BrowserView exists.
     widget_->SetFullscreen(fullscreen);
+
+    // Use a synchronous callback notification on Windows/Linux. Chrome runtime
+    // on Windows/Linux gets notified synchronously via ChromeBrowserDelegate
+    // callbacks when a BrowserView exists. MacOS (both runtimes) gets notified
+    // asynchronously via CefNativeWidgetMac callbacks.
+#if !BUILDFLAG(IS_MAC)
+    if (delegate()) {
+      delegate()->OnWindowFullscreenTransition(this, /*is_completed=*/true);
+    }
+#endif
   }
 }
 
@@ -714,7 +735,7 @@ void CefWindowImpl::RemoveAllAccelerators() {
 }
 
 CefWindowImpl::CefWindowImpl(CefRefPtr<CefWindowDelegate> delegate)
-    : ParentClass(delegate), widget_(nullptr), destroyed_(false) {}
+    : ParentClass(delegate) {}
 
 CefWindowView* CefWindowImpl::CreateRootView() {
   return new CefWindowView(delegate(), this);
@@ -740,4 +761,10 @@ void CefWindowImpl::CreateWidget(gfx::AcceleratedWidget parent_widget) {
   // keep an owned reference.
   std::unique_ptr<views::View> view_ptr = view_util::PassOwnership(this);
   [[maybe_unused]] views::View* view = view_ptr.release();
+
+  initialized_ = true;
+
+  if (delegate()) {
+    delegate()->OnWindowCreated(this);
+  }
 }

libcef/browser/views/window_impl.h

@@ -132,6 +132,7 @@ class CefWindowImpl
   void MenuClosed();
 
   views::Widget* widget() const { return widget_; }
+  bool initialized() const { return initialized_; }
 
  private:
   // Create a new implementation object.
@@ -146,10 +147,13 @@ class CefWindowImpl
   // Initialize the Widget.
   void CreateWidget(gfx::AcceleratedWidget parent_widget);
 
-  views::Widget* widget_;
+  views::Widget* widget_ = nullptr;
+
+  // True if the window has been initialized.
+  bool initialized_ = false;
 
   // True if the window has been destroyed.
-  bool destroyed_;
+  bool destroyed_ = false;
 
   // The currently active menu model and runner.
   CefRefPtr<CefMenuModelImpl> menu_model_;