Consolidate message observer API for win and aura (and touch).

views/widget/native_widget_gtk.cc

 // Copyright (c) 2011 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 "views/widget/native_widget_gtk.h"
 
 #include <gdk/gdk.h>
 #include <gdk/gdkx.h>
 #include <X11/extensions/shape.h>
 #include <X11/Xatom.h>
@@ skipping 242 matching lines @@
 // have no way to tell the difference between a normal drag leave and a drop.
 // To work around that we listen for DROP_START, then ignore the subsequent
 // drag-leave that GTK generates.
 class NativeWidgetGtk::DropObserver : public MessageLoopForUI::Observer {
  public:
   DropObserver() {}
 
   static DropObserver* GetInstance() {
     return Singleton<DropObserver>::get();
   }
+#if defined(TOUCH_UI)
+  virtual base::EventStatus WillProcessEvent(
+      const base::NativeEvent& event) OVERRIDE {
+    return base::EVENT_CONTINUE;
+  }
 
+  virtual void DidProcessEvent(const base::NativeEvent& event) OVERRIDE {
+  }
+#else
   virtual void WillProcessEvent(GdkEvent* event) {

[Ben Goodger (Google), 2011/09/30 20:50:51]

Why are these two branches incompatible? Does GdkEvent* never map to
base::NativeEvent?

[oshima, 2011/09/30 21:17:22]

aura/touch has different signature (returns base::EventStatus) and NativeEvent
is XEvent* on X11/Liinux.
Mapping Gdk to NativeEvent would be tricky because TOUCH build needs NativeEvent
to be XEvent too, which
has TOOLKIT_USES_GTK=1. Once we migrate to aura, this code will be all gone.

     if (event->type == GDK_DROP_START) {
       NativeWidgetGtk* widget = GetNativeWidgetGtkForEvent(event);
       if (widget)
         widget->ignore_drag_leave_ = true;
     }
   }
 
   virtual void DidProcessEvent(GdkEvent* event) {
   }
+#endif
 
  private:
   NativeWidgetGtk* GetNativeWidgetGtkForEvent(GdkEvent* event) {
     GtkWidget* gtk_widget = gtk_get_event_widget(event);
     if (!gtk_widget)
       return NULL;
 
     return static_cast<NativeWidgetGtk*>(
         internal::NativeWidgetPrivate::GetNativeWidgetForNativeView(
             gtk_widget));
@@ skipping 1992 matching lines @@
     button_pressed = event->type == GDK_BUTTON_PRESS ||
         event->type == GDK_2BUTTON_PRESS ||
         event->type == GDK_3BUTTON_PRESS;
     gdk_event_free(event);
   }
   return button_pressed;
 }
 
 }  // namespace internal
 }  // namespace views