Fixing the issue of GDK discarding unsupported XInput events.

base/message_pump_glib_x.h

 // 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.
 
 #ifndef BASE_MESSAGE_PUMP_GLIB_X_H
 #define BASE_MESSAGE_PUMP_GLIB_X_H
 
 #include "base/message_pump.h"
 #include "base/message_pump_glib.h"
 
@@ skipping 13 matching lines @@
   virtual ~MessagePumpGlibX();
 
   // Indicates whether a GDK event was injected by chrome (when |true|) or if it
   // was captured and being processed by GDK (when |false|).
   bool IsDispatchingEvent(void) { return dispatching_event_; }
 
   // Overridden from MessagePumpForUI:
   virtual bool RunOnce(GMainContext* context, bool block);
 
  private:
+  // Some XEvent's can't be directly read from X event queue and will go
+  // through GDK's dispatching process and may get discarded. This function
+  // sets up a filter to intercept those XEvent's we are interested in
+  // and dispatches them so that they won't get lost.
+  static GdkFilterReturn GdkEventFilter(GdkXEvent* gxevent,
+                                        GdkEvent* gevent,
+                                        gpointer data);
+
   static void EventDispatcherX(GdkEvent* event, gpointer data);
 
+  // Decides whether we are interested in processing this XEvent.
+  bool ShouldCaptureXEvent(XEvent* event);
+
+  // Dispatches the XEvent and returns true if we should exit the current loop
+  // of message processing.
+  bool ProcessXEvent(XEvent* event);
+
   // Sends the event to the observers. If an observer returns true, then it does
   // not send the event to any other observers and returns true. Returns false
   // if no observer returns true.
   bool WillProcessXEvent(XEvent* xevent);
 
   // Update the lookup table and flag the events that should be captured and
   // processed so that GDK doesn't get to them.
   void InitializeEventsToCapture(void);
 
 #if defined(HAVE_XINPUT2)
@@ skipping 27 matching lines @@
   // it should be passed on to the default GDK handler.
   std::bitset<LASTEvent> capture_x_events_;
   std::bitset<GDK_EVENT_LAST> capture_gdk_events_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePumpGlibX);
 };
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_PUMP_GLIB_X_H