MacViews: Adds NativeWidgetMac and gets views target compiling on Mac.

ui/views/controls/menu/menu_host.cc

Index: ui/views/controls/menu/menu_host.cc
diff --git a/ui/views/controls/menu/menu_host.cc b/ui/views/controls/menu/menu_host.cc
index ad7915a22eedc3207188a94bfe539a6527e2be6b..98f71e2c24eb8d8f6689985c8a727177b3bef9c6 100644
--- a/ui/views/controls/menu/menu_host.cc
+++ b/ui/views/controls/menu/menu_host.cc
@@ -72,7 +72,9 @@ void MenuHost::ShowMenuHost(bool do_capture) {
   if (do_capture) {
     // Cancel existing touches, so we don't miss some touch release/cancel
     // events due to the menu taking capture.
+#ifdef USE_AURA
     ui::GestureRecognizer::Get()->TransferEventsTo(NULL, NULL);
+#endif

[tapted, 2014/05/21 09:40:29]

This is to resolve

Undefined symbols for architecture i386:
  "ui::GestureRecognizer::Get()", referenced from:
      views::MenuHost::ShowMenuHost(bool) in views.menu_host.o

I wonder if we can just move this into NativeWidgetAura::SetCapture(), or give
that an argument..

[Andre, 2014/05/21 17:13:31]

That symbol was defined the last time I tried to build views.
Looks like gesture_recognizer_impl.cc was changed to be excluded for !aura a few
days ago,
https://codereview.chromium.org/282593002/diff/120001/ui/events/events.gyp

I agree, NativeWidgetAura::SetCapture seems like a better home for this code.

[tapted, 2014/05/22 12:50:14]

I poked at this a bit. Tried out just compiling the gesture stuff again the way
it was last week (crrev/291373002). But there are patches in flight that suggest
more aura-specific stuff on the way. Touch input on desktop OSX isn't currently
a priority AFAIK, so an empty stub felt right for now.

     native_widget_private()->SetCapture();
   }
 }