Ensure that trackpad and trackpoint scrolling works on Windows desktop Aura with legacy trackpad dr…

ui/views/widget/native_widget_win.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.
 
 #include "ui/views/widget/native_widget_win.h"
 
 #include <dwmapi.h>
 #include <shellapi.h>
 
 #include <algorithm>
@@ skipping 751 matching lines @@
     1/gfx::win::GetDeviceScaleFactor(), 0.0,
     0.0, 1/gfx::win::GetDeviceScaleFactor(),
     0.0, 0.0);
   if (event.IsMouseWheelEvent()) {
     ui::MouseWheelEvent dpi_event(
         static_cast<const ui::MouseWheelEvent&>(event));
     dpi_event.UpdateForRootTransform(scale_transform);
     delegate_->OnMouseEvent(&dpi_event);
     return dpi_event.handled();
   } else if (event.IsMouseEvent()) {
-    CHECK(!event.IsScrollEvent()); // Scroll events don't happen in Windows.
     ui::MouseEvent dpi_event(event);
     if (!(dpi_event.flags() & ui::EF_IS_NON_CLIENT))
       dpi_event.UpdateForRootTransform(scale_transform);
     delegate_->OnMouseEvent(&dpi_event);
     return dpi_event.handled();
   }
   NOTREACHED();
   return false;
 }
 
@@ skipping 77 matching lines @@
                                    LPARAM l_param,
                                    LRESULT* result) {
   return false;
 }
 
 void NativeWidgetWin::PostHandleMSG(UINT message,
                                     WPARAM w_param,
                                     LPARAM l_param) {
 }
 
+bool NativeWidgetWin::HandleScrollEvent(const ui::ScrollEvent& event) {
+  delegate_->OnScrollEvent(const_cast<ui::ScrollEvent*>(&event));
+  return event.handled();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // NativeWidgetWin, private:
 
 void NativeWidgetWin::SetInitParams(const Widget::InitParams& params) {
   // Set non-style attributes.
   ownership_ = params.ownership;
 
   ConfigureWindowStyles(message_handler_.get(), params,
                         GetWidget()->widget_delegate(), delegate_);
 
@@ skipping 173 matching lines @@
 // static
 bool NativeWidgetPrivate::IsTouchDown() {
   // This currently isn't necessary because we're not generating touch events on
   // windows.  When we do, this will need to be updated.
   return false;
 }
 
 }  // namespace internal
 
 }  // namespace views