Move WebMouseWheelEvent into its own header file.

content/renderer/input/render_widget_input_handler.cc

 // Copyright 2015 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 "content/renderer/input/render_widget_input_handler.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <utility>
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/trace_event/trace_event_synthetic_delay.h"
 #include "build/build_config.h"
 #include "cc/trees/swap_promise_monitor.h"
 #include "content/common/input/input_event_ack.h"
 #include "content/common/input/input_event_ack_state.h"
 #include "content/public/common/content_switches.h"
 #include "content/renderer/gpu/render_widget_compositor.h"
 #include "content/renderer/ime_event_guard.h"
 #include "content/renderer/input/render_widget_input_handler_delegate.h"
 #include "content/renderer/render_thread_impl.h"
 #include "content/renderer/render_widget.h"
 #include "third_party/WebKit/public/platform/WebFloatPoint.h"
 #include "third_party/WebKit/public/platform/WebFloatSize.h"
 #include "third_party/WebKit/public/platform/WebGestureEvent.h"
+#include "third_party/WebKit/public/platform/WebMouseWheelEvent.h"
 #include "third_party/WebKit/public/platform/scheduler/renderer/renderer_scheduler.h"
 #include "ui/events/blink/web_input_event_traits.h"
 #include "ui/events/latency_info.h"
 #include "ui/gfx/geometry/point_conversions.h"
 
 #if defined(OS_ANDROID)
 #include <android/keycodes.h>
 #endif
 
 using blink::WebFloatPoint;
@@ skipping 420 matching lines @@
   // it can be bundled in the event ack.
   if (handling_event_overscroll_) {
     *handling_event_overscroll_ = std::move(params);
     return;
   }
 
   delegate_->OnDidOverscroll(*params);
 }
 
 }  // namespace content