Get rid of the use_glib gn variable.

base/message_loop/message_pump_glib.h

-// Copyright (c) 2012 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_LOOP_MESSAGE_PUMP_GLIB_H_
-#define BASE_MESSAGE_LOOP_MESSAGE_PUMP_GLIB_H_
-
-#include "base/base_export.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/message_loop/message_pump.h"
-#include "base/observer_list.h"
-#include "base/time/time.h"
-
-typedef struct _GMainContext GMainContext;
-typedef struct _GPollFD GPollFD;
-typedef struct _GSource GSource;
-
-namespace base {
-
-// This class implements a base MessagePump needed for TYPE_UI MessageLoops on
-// platforms using GLib.
-class BASE_EXPORT MessagePumpGlib : public MessagePump {
- public:
-  MessagePumpGlib();
-  ~MessagePumpGlib() override;
-
-  // Internal methods used for processing the pump callbacks.  They are
-  // public for simplicity but should not be used directly.  HandlePrepare
-  // is called during the prepare step of glib, and returns a timeout that
-  // will be passed to the poll. HandleCheck is called after the poll
-  // has completed, and returns whether or not HandleDispatch should be called.
-  // HandleDispatch is called if HandleCheck returned true.
-  int HandlePrepare();
-  bool HandleCheck();
-  void HandleDispatch();
-
-  // Overridden from MessagePump:
-  void Run(Delegate* delegate) override;
-  void Quit() override;
-  void ScheduleWork() override;
-  void ScheduleDelayedWork(const TimeTicks& delayed_work_time) override;
-
- private:
-  bool ShouldQuit() const;
-
-  // We may make recursive calls to Run, so we save state that needs to be
-  // separate between them in this structure type.
-  struct RunState;
-
-  RunState* state_;
-
-  // This is a GLib structure that we can add event sources to.  We use the
-  // default GLib context, which is the one to which all GTK events are
-  // dispatched.
-  GMainContext* context_;
-
-  // This is the time when we need to do delayed work.
-  TimeTicks delayed_work_time_;
-
-  // The work source.  It is shared by all calls to Run and destroyed when
-  // the message pump is destroyed.
-  GSource* work_source_;
-
-  // We use a wakeup pipe to make sure we'll get out of the glib polling phase
-  // when another thread has scheduled us to do some work.  There is a glib
-  // mechanism g_main_context_wakeup, but this won't guarantee that our event's
-  // Dispatch() will be called.
-  int wakeup_pipe_read_;
-  int wakeup_pipe_write_;
-  // Use a scoped_ptr to avoid needing the definition of GPollFD in the header.
-  scoped_ptr<GPollFD> wakeup_gpollfd_;
-
-  DISALLOW_COPY_AND_ASSIGN(MessagePumpGlib);
-};
-
-}  // namespace base
-
-#endif  // BASE_MESSAGE_LOOP_MESSAGE_PUMP_GLIB_H_