Delay instantiating InputDeviceCapabilities until accessed.

third_party/WebKit/Source/core/events/UIEvent.cpp

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "core/events/UIEvent.h"
 
-#include "core/input/InputDeviceCapabilities.h"
-
 namespace blink {
 
 UIEvent::UIEvent() : m_detail(0), m_sourceCapabilities(nullptr) {}
 
 UIEvent::UIEvent(const AtomicString& eventType,
                  bool canBubbleArg,
                  bool cancelableArg,
                  ComposedMode composedMode,
                  TimeTicks platformTimeStamp,
                  AbstractView* viewArg,
                  int detailArg,
-                 InputDeviceCapabilities* sourceCapabilitiesArg)
+                 const InputDeviceCapabilitiesValue& sourceCapabilitiesArg)
     : Event(eventType,
             canBubbleArg,
             cancelableArg,
             composedMode,
             platformTimeStamp),
       m_view(viewArg),
       m_detail(detailArg),
       m_sourceCapabilities(sourceCapabilitiesArg) {}
 
 UIEvent::UIEvent(const AtomicString& eventType, const UIEventInit& initializer)
     : Event(eventType, initializer),
       m_view(initializer.view()),
       m_detail(initializer.detail()),
       m_sourceCapabilities(initializer.sourceCapabilities()) {}
 
 UIEvent::~UIEvent() {}
 
 void UIEvent::initUIEvent(const AtomicString& typeArg,
                           bool canBubbleArg,
                           bool cancelableArg,
                           AbstractView* viewArg,
                           int detailArg) {
   initUIEventInternal(typeArg, canBubbleArg, cancelableArg, nullptr, viewArg,
-                      detailArg, nullptr);
+                      detailArg, InputDeviceCapabilities::Null);
 }
 
 void UIEvent::initUIEventInternal(
     const AtomicString& typeArg,
     bool canBubbleArg,
     bool cancelableArg,
     EventTarget* relatedTarget,
     AbstractView* viewArg,
     int detailArg,
-    InputDeviceCapabilities* sourceCapabilitiesArg) {
+    const InputDeviceCapabilitiesValue& sourceCapabilitiesArg) {
   if (isBeingDispatched())
     return;
 
   initEvent(typeArg, canBubbleArg, cancelableArg, relatedTarget);
 
   m_view = viewArg;
   m_detail = detailArg;
   m_sourceCapabilities = sourceCapabilitiesArg;
 }
 
 bool UIEvent::isUIEvent() const {
   return true;
 }
 
 const AtomicString& UIEvent::interfaceName() const {
   return EventNames::UIEvent;
 }
 
 int UIEvent::which() const {
   return 0;
 }
 
+InputDeviceCapabilities* UIEvent::sourceCapabilities() {
+  // TODO: align with what the spec decides for the scope of
+  // |sourceCapabilities|. i.e., the returned instance may end up as being
+  // unique per-UIEvent, not window.
+  return m_sourceCapabilities.getCapabilities(m_view);
+}
+
 DEFINE_TRACE(UIEvent) {
   visitor->trace(m_view);
   visitor->trace(m_sourceCapabilities);
   Event::trace(visitor);
 }
 
 }  // namespace blink