Allow a View to specify a non-default native theme (i.e. different from

ui/views/view.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #define _USE_MATH_DEFINES // For VC++ to get M_PI. This has to be first.
 
 #include "ui/views/view.h"
 
 #include <algorithm>
 #include <cmath>
@@ skipping 906 matching lines @@
 void View::SetBorder(std::unique_ptr<Border> b) {
   border_ = std::move(b);
 }
 
 const ui::ThemeProvider* View::GetThemeProvider() const {
   const Widget* widget = GetWidget();
   return widget ? widget->GetThemeProvider() : nullptr;
 }
 
 const ui::NativeTheme* View::GetNativeTheme() const {
+  if (native_theme_)
+    return native_theme_;
+
+  if (parent())
+    return parent()->GetNativeTheme();
+
   const Widget* widget = GetWidget();
   if (widget)
     return widget->GetNativeTheme();
 
   return ui::NativeTheme::GetInstanceForNativeUi();
 }
 
+void View::SetNativeTheme(ui::NativeTheme* theme) {
+  ui::NativeTheme* original_native_theme = GetNativeTheme();
+  native_theme_ = theme;
+  if (native_theme_ != original_native_theme)
+    PropagateNativeThemeChanged(theme);
+}
+
 // RTL painting ----------------------------------------------------------------
 
 void View::EnableCanvasFlippingForRTLUI(bool enable) {
   flip_canvas_on_paint_for_rtl_ui_ = enable;
 }
 
 // Input -----------------------------------------------------------------------
 
 View* View::GetEventHandlerForPoint(const gfx::Point& point) {
   return GetEventHandlerForRect(gfx::Rect(point, gfx::Size(1, 1)));
@@ skipping 1024 matching lines @@
       if (details.child == this)
         UnregisterAccelerators(true);
     }
   }
 
   ViewHierarchyChanged(details);
   details.parent->needs_layout_ = true;
 }
 
 void View::PropagateNativeThemeChanged(const ui::NativeTheme* theme) {
+  if (native_theme_ && native_theme_ != theme)
+    return;
+
   {
     internal::ScopedChildrenLock lock(this);
     for (auto* child : children_)
       child->PropagateNativeThemeChanged(theme);
   }
   OnNativeThemeChanged(theme);
 }
 
 // Size and disposition --------------------------------------------------------
 
@@ skipping 542 matching lines @@
   // Message the RootView to do the drag and drop. That way if we're removed
   // the RootView can detect it and avoid calling us back.
   gfx::Point widget_location(event.location());
   ConvertPointToWidget(this, &widget_location);
   widget->RunShellDrag(this, data, widget_location, drag_operations, source);
   // WARNING: we may have been deleted.
   return true;
 }
 
 }  // namespace views