Add PlatformWindow/Event related code for Ozone X11.

ui/events/platform/x11/x11_event_source.cc

Index: ui/events/platform/x11/x11_event_source.cc
diff --git a/ui/events/platform/x11/x11_event_source.cc b/ui/events/platform/x11/x11_event_source.cc
index ba55e0b1751a92eec498934a293125f6b87ded90..d9891ddff8f5a0d045f67fbefc2667f3dd53d371 100644
--- a/ui/events/platform/x11/x11_event_source.cc
+++ b/ui/events/platform/x11/x11_event_source.cc
@@ -94,6 +94,15 @@ X11EventSource* X11EventSource::GetInstance() {
 ////////////////////////////////////////////////////////////////////////////////
 // X11EventSource, public
 
+void X11EventSource::AddXEventDispatcher(XEventDispatcher* dispatcher) {
+  CHECK(dispatcher);

[spang, 2016/01/26 21:37:40]

CHECK is not allowed except for security-critical assertions. Use DCHECK or no
check.

[kylechar, 2016/01/27 15:39:26]

Done.

+  x_dispatchers_.AddObserver(dispatcher);
+}
+
+void X11EventSource::RemoveXEventDispatcher(XEventDispatcher* dispatcher) {
+  x_dispatchers_.RemoveObserver(dispatcher);
+}
+
 void X11EventSource::DispatchXEvents() {
   DCHECK(display_);
   // Handle all pending events.
@@ -132,8 +141,17 @@ uint32_t X11EventSource::ExtractCookieDataDispatchEvent(XEvent* xevent) {
   return action;
 }
 
-uint32_t X11EventSource::DispatchEvent(XEvent* xevent) {
-  uint32_t action = PlatformEventSource::DispatchEvent(xevent);
+void X11EventSource::DispatchXEventToXEventDispatchers(XEvent* xevent) {
+  if (x_dispatchers_.might_have_observers()) {
+    base::ObserverList<XEventDispatcher>::Iterator iter(&x_dispatchers_);
+    while (XEventDispatcher* dispatcher = iter.GetNext()) {
+      if (dispatcher->DispatchXEvent(*xevent))
+        break;

[spang, 2016/01/26 21:37:40]

If DispatchXEvent returns true, do we still try to turn it into a PlatformEvent?
We probably shouldn't.

[kylechar, 2016/01/27 15:39:26]

It doesn't right now because it actually happens in the opposite order, only if
we can't turn it into a PlatfromEvent(ui::Event) then we try to dispatch it as
an XEvent. If I invert the order I'll ensure that doesn't happen.

+    }
+  }
+}
+
+void X11EventSource::PostDispatchEvent(XEvent* xevent) {
   if (xevent->type == GenericEvent &&
       (xevent->xgeneric.evtype == XI_HierarchyChanged ||
        xevent->xgeneric.evtype == XI_DeviceChanged)) {
@@ -147,7 +165,6 @@ uint32_t X11EventSource::DispatchEvent(XEvent* xevent) {
     // Clear stored scroll data
     ui::DeviceDataManagerX11::GetInstance()->InvalidateScrollClasses();
   }
-  return action;
 }
 
 void X11EventSource::StopCurrentEventStream() {