Add PlatformWindow/Event related code for Ozone X11.

ui/events/platform/x11/x11_event_source.h

 // Copyright 2014 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.
 
 #ifndef UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_H_
 #define UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/observer_list.h"
 #include "ui/events/events_export.h"
 #include "ui/events/platform/platform_event_source.h"
 #include "ui/gfx/x/x11_types.h"
 
 typedef struct _GPollFD GPollFD;
 typedef struct _GSource GSource;
 typedef union _XEvent XEvent;
 typedef unsigned long XID;
 
 namespace ui {
 
+// Interface for classes that want to receive XEvent directly. Only used with
+// ozone_platform_x11 and only events that can't be translated into ui::Events
+// are sent via this path.
+class EVENTS_EXPORT XEventDispatcher {
+ public:
+  // Sends XEvent to XEventDispatcher for handling. Returns true if the XEvent
+  // was dispatched, otherwise false. After the first XEventDispatcher returns
+  // true XEvent dispatching stops.
+  virtual bool DispatchXEvent(const XEvent& event) = 0;
+
+ protected:
+  virtual ~XEventDispatcher() {}
+};
+
 class X11HotplugEventHandler;
 
 // A PlatformEventSource implementation for reading events from X11 server and
 // dispatching the events to the appropriate dispatcher.
 class EVENTS_EXPORT X11EventSource : public PlatformEventSource {
  public:
   explicit X11EventSource(XDisplay* display);
   ~X11EventSource() override;
 
   static X11EventSource* GetInstance();
 
+  // Adds a XEvent dispatcher to the dispatcher list.
+  void AddXEventDispatcher(XEventDispatcher* dispatcher);
+
+  // Removes a XEvent dispatcher from the dispatcher list.
+  void RemoveXEventDispatcher(XEventDispatcher* dispatcher);
+
   // Called by the glib source dispatch function. Processes all (if any)
   // available X events.
   void DispatchXEvents();
 
   // Blocks on the X11 event queue until we receive notification from the
   // xserver that |w| has been mapped; StructureNotifyMask events on |w| are
   // pulled out from the queue and dispatched out of order.
   //
   // For those that know X11, this is really a wrapper around XWindowEvent
   // which still makes sure the preempted event is dispatched instead of
   // dropped on the floor. This method exists because mapping a window is
   // asynchronous (and we receive an XEvent when mapped), while there are also
   // functions which require a mapped window.
   void BlockUntilWindowMapped(XID window);
 
  protected:
   XDisplay* display() { return display_; }
 
  private:
   // Extracts cookie data from |xevent| if it's of GenericType, and dispatches
   // the event. This function also frees up the cookie data after dispatch is
   // complete.
   uint32_t ExtractCookieDataDispatchEvent(XEvent* xevent);
 
   // PlatformEventSource:
-  uint32_t DispatchEvent(XEvent* xevent) override;
+  uint32_t DispatchEvent(base::NativeEvent native_event) override;
   void StopCurrentEventStream() override;
   void OnDispatcherListChanged() override;
 
+  // Sends XEvent to registered XEventDispatchers.
+  void DispatchXEventToXEventDispatchers(XEvent* xevent);
+
+  // Handles updates after event has been dispatched.
+  void PostDispatchEvent(XEvent* xevent);
+
   // The connection to the X11 server used to receive the events.
   XDisplay* display_;
 
   // Keeps track of whether this source should continue to dispatch all the
   // available events.
   bool continue_stream_;
 
   scoped_ptr<X11HotplugEventHandler> hotplug_event_handler_;
 
+  // Keep track of all XEventDispatcher to send XEvents directly to, only used
+  // with ozone.

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

Why "only used with ozone" ?

I think anything that would be plumbed through this on ozone could do so on
cros-x11 & desktop as well. Then you won't need any ifdef in the GLX code, for
example.

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

As long as there are no PlatformEventObservers in USE_X11 that care about that
type of event (which doesn't appear to be the case) that would totally work and
make things simpler. It might be a little weird though because PlatformEvent is
also an XEvent in USE_X11 build.

[kylechar, 2016/02/01 16:44:27]

After talking with Sadrul we decided that only X11EventSourceOzone will maintain
a list of XEventDispatchers.

+  base::ObserverList<XEventDispatcher> x_dispatchers_;
+
   DISALLOW_COPY_AND_ASSIGN(X11EventSource);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_H_