Remove windows/mac/ios specific code from //ui

ui/events/gestures/gesture_recognizer_impl_mac.cc

-// 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.
-
-#include "base/macros.h"
-#include "ui/events/gestures/gesture_recognizer.h"
-
-namespace ui {
-
-namespace {
-
-// Stub implementation of GestureRecognizer for Mac. Currently only serves to
-// provide a no-op implementation of TransferEventsTo().
-class GestureRecognizerImplMac : public GestureRecognizer {
- public:
-  GestureRecognizerImplMac() {}
-  ~GestureRecognizerImplMac() override {}
-
- private:
-  bool ProcessTouchEventPreDispatch(const TouchEvent& event,
-                                    GestureConsumer* consumer) override {
-    return false;
-  }
-
-  Gestures* ProcessTouchEventPostDispatch(const TouchEvent& event,
-                                          ui::EventResult result,
-                                          GestureConsumer* consumer) override {
-    return NULL;
-  }
-  Gestures* ProcessTouchEventOnAsyncAck(const TouchEvent& event,
-                                        ui::EventResult result,
-                                        GestureConsumer* consumer) override {
-    return NULL;
-  };
-  bool CleanupStateForConsumer(GestureConsumer* consumer) override {
-    return false;
-  }
-  GestureConsumer* GetTouchLockedTarget(const TouchEvent& event) override {
-    return NULL;
-  }
-  GestureConsumer* GetTargetForGestureEvent(
-      const GestureEvent& event) override {
-    return NULL;
-  }
-  GestureConsumer* GetTargetForLocation(const gfx::PointF& location,
-                                        int source_device_id) override {
-    return NULL;
-  }
-  void TransferEventsTo(GestureConsumer* current_consumer,
-                        GestureConsumer* new_consumer) override {}
-  bool GetLastTouchPointForTarget(GestureConsumer* consumer,
-                                  gfx::PointF* point) override {
-    return false;
-  }
-  bool CancelActiveTouches(GestureConsumer* consumer) override { return false; }
-  void AddGestureEventHelper(GestureEventHelper* helper) override {}
-  void RemoveGestureEventHelper(GestureEventHelper* helper) override {}
-
-  DISALLOW_COPY_AND_ASSIGN(GestureRecognizerImplMac);
-};
-
-}  // namespace
-
-// static
-GestureRecognizer* GestureRecognizer::Get() {
-  CR_DEFINE_STATIC_LOCAL(GestureRecognizerImplMac, instance, ());
-  return &instance;
-}
-
-}  // namespace ui