aura: Make sure event copying works properly for X11.

This includes two changes:
 * In X11, copying event is tricky, especially for XInput2 events. So avoid
   doing that when possible.
 * Mouse-wheel events used to piggy-back on MouseEvents during dispatch, and
   the offset used to be extracted from the native-event. Fix this to make sure
   the wheel-events are more like scroll-events so that the offset is carried
   with the ui::Event during dispatch to avoid dependency on the native-event.

BUG=144211

Review URL: https://chromiumcodereview.appspot.com/10875018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@153094 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 32 insertions, 5 deletions

diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index 797560b..d274b86 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -1025,9 +1025,16 @@ bool RootWindow::DispatchMouseEventToTarget(ui::MouseEvent* event,
     Window::ConvertPointToTarget(this, target, &location_in_window);
     if (IsNonClientLocation(target, location_in_window))
       flags |= ui::EF_IS_NON_CLIENT;
-    ui::MouseEvent translated_event(
-        *event, static_cast<Window*>(this), target, event->type(), flags);
-    return ProcessMouseEvent(target, &translated_event);
+    if (event->type() == ui::ET_MOUSEWHEEL) {
+      ui::MouseWheelEvent translated_event(
+          *static_cast<ui::MouseWheelEvent*>(event),
+          static_cast<Window*>(this), target, event->type(), flags);
+      return ProcessMouseEvent(target, &translated_event);
+    } else {
+      ui::MouseEvent translated_event(
+          *event, static_cast<Window*>(this), target, event->type(), flags);
+      return ProcessMouseEvent(target, &translated_event);
+    }
   }
   return false;
 }
diff --git a/ui/aura/root_window_host_linux.cc b/ui/aura/root_window_host_linux.cc
index 503286d..bcf1b6f 100644
--- a/ui/aura/root_window_host_linux.cc
+++ b/ui/aura/root_window_host_linux.cc
@@ -638,7 +638,6 @@ bool RootWindowHostLinux::Dispatch(const base::NativeEvent& event) {
         case ui::ET_MOUSE_DRAGGED:
         case ui::ET_MOUSE_PRESSED:
         case ui::ET_MOUSE_RELEASED:
-        case ui::ET_MOUSEWHEEL:
         case ui::ET_MOUSE_ENTERED:
         case ui::ET_MOUSE_EXITED: {
           if (type == ui::ET_MOUSE_MOVED || type == ui::ET_MOUSE_DRAGGED) {
@@ -670,6 +669,11 @@ bool RootWindowHostLinux::Dispatch(const base::NativeEvent& event) {
           delegate_->OnHostMouseEvent(&mouseev);
           break;
         }
+        case ui::ET_MOUSEWHEEL: {
+          ui::MouseWheelEvent mouseev(xev);
+          delegate_->OnHostMouseEvent(&mouseev);
+          break;
+        }
         case ui::ET_SCROLL_FLING_START:
         case ui::ET_SCROLL_FLING_CANCEL:
         case ui::ET_SCROLL: {
diff --git a/ui/base/event.cc b/ui/base/event.cc
index 2db3b09..1b31197 100644
--- a/ui/base/event.cc
+++ b/ui/base/event.cc
@@ -23,6 +23,8 @@ namespace {
 
 base::NativeEvent CopyNativeEvent(const base::NativeEvent& event) {
 #if defined(USE_X11)
+  if (!event || event->type == GenericEvent)
+    return NULL;
   XEvent* copy = new XEvent;
   *copy = *event;
   return copy;
@@ -74,11 +76,15 @@ Event::Event(const base::NativeEvent& native_event,
 }
 
 Event::Event(const Event& copy)
-    : native_event_(copy.native_event_),
+    : native_event_(::CopyNativeEvent(copy.native_event_)),
       type_(copy.type_),
       time_stamp_(copy.time_stamp_),
       flags_(copy.flags_),
       delete_native_event_(false) {
+#if defined(USE_X11)
+  if (native_event_)
+    delete_native_event_ = true;
+#endif
 }
 
 void Event::Init() {
diff --git a/ui/base/event.h b/ui/base/event.h
index c34b914..fe4a1e4 100644
--- a/ui/base/event.h
+++ b/ui/base/event.h
@@ -294,6 +294,16 @@ class UI_EXPORT MouseWheelEvent : public MouseEvent {
   explicit MouseWheelEvent(const MouseEvent& mouse_event);
   explicit MouseWheelEvent(const ScrollEvent& scroll_event);
 
+  template <class T>
+  MouseWheelEvent(const MouseWheelEvent& model,
+                  T* source,
+                  T* target,
+                  EventType type,
+                  int flags)
+      : MouseEvent(model, source, target, type, flags),
+        offset_(model.offset_) {
+  }
+
   // The amount to scroll. This is in multiples of kWheelDelta.
   // Note: offset() > 0 means scroll up / left.
   int offset() const { return offset_; }