Collapse the API surface on WebInputEvent via accessor functions.

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

Index: third_party/WebKit/Source/core/events/MouseEvent.cpp
diff --git a/third_party/WebKit/Source/core/events/MouseEvent.cpp b/third_party/WebKit/Source/core/events/MouseEvent.cpp
index 5d64a5f5e3706ea417a46679bf28ccade7d680b9..da7a86940579bae1224eb6205bbe0702544c44a4 100644
--- a/third_party/WebKit/Source/core/events/MouseEvent.cpp
+++ b/third_party/WebKit/Source/core/events/MouseEvent.cpp
@@ -195,8 +195,8 @@ MouseEvent::MouseEvent(
           cancelable,
           abstractView,
           0,
-          static_cast<PlatformEvent::Modifiers>(event.modifiers),
-          TimeTicks::FromSeconds(event.timeStampSeconds),
+          static_cast<PlatformEvent::Modifiers>(event.modifiers()),
+          TimeTicks::FromSeconds(event.timeStampSeconds()),
           syntheticEventType == PlatformMouseEvent::FromTouch
               ? InputDeviceCapabilities::firesTouchEventsSourceCapabilities()
               : InputDeviceCapabilities::
@@ -207,7 +207,7 @@ MouseEvent::MouseEvent(
                          ? PositionType::Positionless
                          : PositionType::Position),
       m_button(0),
-      m_buttons(platformModifiersToButtons(event.modifiers)),
+      m_buttons(platformModifiersToButtons(event.modifiers())),
       m_syntheticEventType(syntheticEventType),
       m_region(region) {
   IntPoint rootFrameCoordinates = flooredIntPoint(event.positionInRootFrame());