Fix theme change paint issue on linux.

ui/views/widget/widget.cc

Index: ui/views/widget/widget.cc
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index 61469a8971df52d18c504cb3ea8fa1155d77782d..118a118b20e9dbe799b56f8c14f99b2b22ee459f 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -166,8 +166,7 @@ Widget::Widget()
       auto_release_capture_(true),
       root_layers_dirty_(false),
       movement_disabled_(false),
-      observer_manager_(this),
-      processing_theme_changed_(false) {
+      observer_manager_(this) {
 }
 
 Widget::~Widget() {
@@ -901,8 +900,6 @@ void Widget::DebugToggleFrameType() {
 }
 
 void Widget::FrameTypeChanged() {
-  if (processing_theme_changed_)
-    return;
   native_widget_->FrameTypeChanged();
 }
 
@@ -1366,10 +1363,6 @@ void Widget::OnNativeThemeUpdated(ui::NativeTheme* observed_theme) {
     observer_manager_.Add(current_native_theme);
   }
 
-  DCHECK_EQ(processing_theme_changed_, false);
-
-  base::AutoReset<bool> auto_theme_changed_recursion_break(
-      &processing_theme_changed_, true);
   root_view_->PropagateNativeThemeChanged(current_native_theme);
 }