Give MainThreadEventQueue a mutable WebInputEvent.

content/common/input/event_with_latency_info.cc

 // Copyright 2016 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/common/input/event_with_latency_info.h"
 
 #include <bitset>
 #include <limits>
 #include "content/common/input/web_input_event_traits.h"
 
@@ skipping 236 matching lines @@
   if (event_to_coalesce.type == blink::WebInputEvent::MouseWheel &&
       event->type == blink::WebInputEvent::MouseWheel) {
     Coalesce(static_cast<const blink::WebMouseWheelEvent&>(event_to_coalesce),
              static_cast<blink::WebMouseWheelEvent*>(event));
   }
 }
 
 }  // namespace internal
 
 ScopedWebInputEventWithLatencyInfo::ScopedWebInputEventWithLatencyInfo(
-    const WebInputEvent& event,
+    ScopedWebInputEvent event,
     const ui::LatencyInfo& latency_info)
-    : event_(WebInputEventTraits::Clone(event)), latency_(latency_info) {}
+    : event_(std::move(event)), latency_(latency_info) {
+}
 
 ScopedWebInputEventWithLatencyInfo::~ScopedWebInputEventWithLatencyInfo() {}
 
 bool ScopedWebInputEventWithLatencyInfo::CanCoalesceWith(
     const ScopedWebInputEventWithLatencyInfo& other) const {
   return internal::CanCoalesce(other.event(), event());
 }
 
 void ScopedWebInputEventWithLatencyInfo::CoalesceWith(
     const ScopedWebInputEventWithLatencyInfo& other) {
@@ skipping 15 matching lines @@
 
 const blink::WebInputEvent& ScopedWebInputEventWithLatencyInfo::event() const {
   return *event_;
 }
 
 blink::WebInputEvent& ScopedWebInputEventWithLatencyInfo::event() {
   return *event_;
 }
 
 }  // namespace content