Avoid possible reentrancy of ThemeChanged (see #3671)

The call to SelectNativeTheme from ChromeBrowserFrame::Initialized was
causing Widget::ThemeChanged reentrancy via OnColorProviderCacheResetMissed
when running with `--enable-chrome-runtime --use-native`. Make all calls to
ThemeChanged async to avoid this and possible future issues.

libcef/browser/chrome/views/chrome_browser_frame.cc

@@ -5,6 +5,7 @@
 #include "libcef/browser/chrome/views/chrome_browser_frame.h"
 
 #include "libcef/browser/chrome/chrome_browser_host_impl.h"
+#include "libcef/browser/thread_util.h"
 #include "libcef/browser/views/window_view.h"
 
 #include "chrome/browser/themes/theme_service.h"
@@ -93,10 +94,7 @@ void ChromeBrowserFrame::UserChangedTheme(
   // Calls ThemeChanged() and possibly SelectNativeTheme().
   BrowserFrame::UserChangedTheme(theme_change_type);
 
-  if (window_view_) {
+  NotifyThemeColorsChanged(/*chrome_theme=*/!native_theme_change_);
-    window_view_->OnThemeColorsChanged(/*chrome_theme=*/!native_theme_change_);
-    ThemeChanged();
-  }
 }
 
 views::internal::RootView* ChromeBrowserFrame::CreateRootView() {
@@ -156,8 +154,15 @@ void ChromeBrowserFrame::OnColorProviderCacheResetMissed() {
     return;
   }
 
+  NotifyThemeColorsChanged(/*chrome_theme=*/false);
+}
+
+void ChromeBrowserFrame::NotifyThemeColorsChanged(bool chrome_theme) {
   if (window_view_) {
-    window_view_->OnThemeColorsChanged(/*chrome_theme=*/false);
+    window_view_->OnThemeColorsChanged(chrome_theme);
-    ThemeChanged();
+
+    // Call ThemeChanged() asynchronously to avoid possible reentrancy.
+    CEF_POST_TASK(TID_UI, base::BindOnce(&ChromeBrowserFrame::ThemeChanged,
+                                         weak_ptr_factory_.GetWeakPtr()));
   }
 }

libcef/browser/chrome/views/chrome_browser_frame.h

@@ -9,6 +9,7 @@
 #include "libcef/browser/views/color_provider_tracker.h"
 #include "libcef/browser/views/widget.h"
 
+#include "base/memory/weak_ptr.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/views/frame/browser_frame.h"
 
@@ -136,6 +137,8 @@ class ChromeBrowserFrame : public BrowserFrame,
   // CefColorProviderTracker::Observer methods:
   void OnColorProviderCacheResetMissed() override;
 
+  void NotifyThemeColorsChanged(bool chrome_theme);
+
   CefWindowView* window_view_;
   BrowserView* browser_view_ = nullptr;
 
@@ -143,6 +146,8 @@ class ChromeBrowserFrame : public BrowserFrame,
   bool native_theme_change_ = false;
 
   CefColorProviderTracker color_provider_tracker_{this};
+
+  base::WeakPtrFactory<ChromeBrowserFrame> weak_ptr_factory_{this};
 };
 
 #endif  // CEF_LIBCEF_BROWSER_CHROME_VIEWS_CHROME_BROWSER_FRAME_H_

libcef/browser/views/widget_impl.cc

@@ -4,6 +4,7 @@
 
 #include "libcef/browser/views/widget_impl.h"
 
+#include "libcef/browser/thread_util.h"
 #include "libcef/browser/views/window_view.h"
 #include "libcef/features/runtime.h"
 
@@ -226,7 +227,9 @@ void CefWidgetImpl::NotifyThemeColorsChanged(bool chrome_theme,
   if (window_view_) {
     window_view_->OnThemeColorsChanged(chrome_theme);
     if (call_theme_changed) {
-      ThemeChanged();
+      // Call ThemeChanged() asynchronously to avoid possible reentrancy.
+      CEF_POST_TASK(TID_UI, base::BindOnce(&CefWidgetImpl::ThemeChanged,
+                                           weak_ptr_factory_.GetWeakPtr()));
     }
   }
 }

libcef/browser/views/widget_impl.h

@@ -11,6 +11,7 @@
 #include "libcef/browser/views/color_provider_tracker.h"
 #include "libcef/browser/views/widget.h"
 
+#include "base/memory/weak_ptr.h"
 #include "chrome/browser/themes/theme_service_observer.h"
 #include "ui/views/widget/widget.h"
 
@@ -91,6 +92,8 @@ class CefWidgetImpl : public views::Widget,
   ProfileMap associated_profiles_;
 
   CefColorProviderTracker color_provider_tracker_{this};
+
+  base::WeakPtrFactory<CefWidgetImpl> weak_ptr_factory_{this};
 };
 
 #endif  // CEF_LIBCEF_BROWSER_VIEWS_WIDGET_IMPL_H_