Handle alternate types in HandleMouseEvent.

ui/views/widget/native_widget_win.cc

Index: ui/views/widget/native_widget_win.cc
diff --git a/ui/views/widget/native_widget_win.cc b/ui/views/widget/native_widget_win.cc
index 2123600168a169c4d30f013f019e2a742a678971..f46284f567dd29ef1d3d0f1e6bf28b96a3e59d8c 100644
--- a/ui/views/widget/native_widget_win.cc
+++ b/ui/views/widget/native_widget_win.cc
@@ -743,11 +743,32 @@ void NativeWidgetWin::HandleNativeBlur(HWND focused_window) {
 }
 
 bool NativeWidgetWin::HandleMouseEvent(const ui::MouseEvent& event) {
-  ui::MouseEvent dpi_event(event);
-  dpi_event.set_location(ui::win::ScreenToDIPPoint(event.location()));
-  dpi_event.set_root_location(ui::win::ScreenToDIPPoint(event.location()));
-  delegate_->OnMouseEvent(&dpi_event);
-  return dpi_event.handled();
+  if (event.IsMouseWheelEvent()) {
+    ui::MouseWheelEvent dpi_event(event,
+      static_cast<const ui::MouseWheelEvent&>(event).x_offset() /
+      ui::win::GetDeviceScaleFactor(),
+      static_cast<const ui::MouseWheelEvent&>(event).y_offset() /
+      ui::win::GetDeviceScaleFactor());

[sadrul, 2013/06/24 02:09:35]

Most of the ui::Events are copyable. Looks like MouseWheelEvents aren't. It
probably makes more sense to just allow copying a MouseWheelEvent, so you can
just do:
  ui::MouseWheelEvent dpi_event(event);
(like for the MouseEvent case below)

[girard, 2013/06/24 20:37:07]

If we do this, we'd still need the static_cast in the call to the c'tor. (No big
deal). We would also need to expose a set_x_offset()/set_y_offset().

I think a cleaner approach would be to switch to a call to
UpdateForRootTransform() after constructing either event, and implement
MouseWheelEvent::UpdateForRootTransform.

+    dpi_event.set_location(ui::win::ScreenToDIPPoint(event.location()));
+    dpi_event.set_root_location(ui::win::ScreenToDIPPoint(event.location()));
+    delegate_->OnMouseEvent(&dpi_event);
+    return dpi_event.handled();
+  } else if (event.IsScrollEvent()) {

[sadrul, 2013/06/24 02:09:35]

scroll events (i.e. ET_SCROLL*) are never generated on windows. So you can
simplify this:
  if (event.type() == ui::ET_MOUSEWHEEL) {
    ...
  } else {
    CHECK(!event.IsScrollEvent());  <-- not really necessary
    ...
  }

[girard, 2013/06/24 20:37:07]

Thanks - cleaned this up. (I was trying to be more conservative/paranoid on the
types supported.)

+    ui::ScrollEvent dpi_event(static_cast<const ui::ScrollEvent&>(event));
+    dpi_event.Scale(1/ui::win::GetDeviceScaleFactor());
+    dpi_event.set_location(ui::win::ScreenToDIPPoint(event.location()));
+    dpi_event.set_root_location(ui::win::ScreenToDIPPoint(event.location()));
+    delegate_->OnMouseEvent(&dpi_event);
+    return dpi_event.handled();
+  } else if (event.IsMouseEvent()) {
+    ui::MouseEvent dpi_event(event);
+    dpi_event.set_location(ui::win::ScreenToDIPPoint(event.location()));
+    dpi_event.set_root_location(ui::win::ScreenToDIPPoint(event.location()));
+    delegate_->OnMouseEvent(&dpi_event);
+    return dpi_event.handled();
+  }
+  NOTREACHED();
+  return false;
 }
 
 bool NativeWidgetWin::HandleKeyEvent(const ui::KeyEvent& event) {