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

chrome/browser/notifications/balloon_collection_gtk.cc

Index: chrome/browser/notifications/balloon_collection_gtk.cc
diff --git a/chrome/browser/notifications/balloon_collection_linux.cc b/chrome/browser/notifications/balloon_collection_gtk.cc
similarity index 88%
rename from chrome/browser/notifications/balloon_collection_linux.cc
rename to chrome/browser/notifications/balloon_collection_gtk.cc
index 0255ae839faea607ff0d5ac29365da1b84ccb308..2420735f72016bcb90b005615545ae8ed5203de6 100644
--- a/chrome/browser/notifications/balloon_collection_linux.cc
+++ b/chrome/browser/notifications/balloon_collection_gtk.cc
@@ -39,6 +39,19 @@ void BalloonCollectionImpl::PositionBalloons(bool reposition) {
   PositionBalloonsInternal(reposition);
 }
 
+#if defined(TOUCH_UI)
+base::EventStatus BalloonCollectionImpl::WillProcessEvent(
+    const base::NativeEvent& event) {
+  return base::EVENT_CONTINUE;
+}
+
+void BalloonCollectionImpl::DidProcessEvent(const base::NativeEvent& event) {
+  NOTIMPLEMENTED();
+}
+#else
+void BalloonCollectionImpl::WillProcessEvent(GdkEvent* event) {
+}
+
 void BalloonCollectionImpl::DidProcessEvent(GdkEvent* event) {
   switch (event->type) {
     case GDK_MOTION_NOTIFY:
@@ -49,6 +62,7 @@ void BalloonCollectionImpl::DidProcessEvent(GdkEvent* event) {
       break;
   }
 }
+#endif
 
 bool BalloonCollectionImpl::IsCursorInBalloonCollection() const {
   GdkScreen* screen = gdk_screen_get_default();