Collapse the API surface on WebInputEvent via accessor functions.

ui/events/blink/web_input_event.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 "ui/events/blink/web_input_event.h"
 
 #include "ui/events/base_event_utils.h"
 #include "ui/events/blink/blink_event_util.h"
 #include "ui/events/event.h"
 #include "ui/events/event_utils.h"
@@ skipping 90 matching lines @@
       break;
     default:
       NOTREACHED();
   }
 
   blink::WebKeyboardEvent webkit_event(
       type, EventFlagsToWebEventModifiers(event.flags()) |
                 DomCodeToWebInputEventModifiers(event.code()),
       EventTimeStampToSeconds(event.time_stamp()));
 
-  if (webkit_event.modifiers & blink::WebInputEvent::AltKey)
+  if (webkit_event.modifiers() & blink::WebInputEvent::AltKey)
     webkit_event.isSystemKey = true;
 
   // TODO(dtapuska): crbug.com/570388. Ozone appears to deliver
   // key_code events that aren't "located" for the keypad like
   // Windows and X11 do and blink expects.
   webkit_event.windowsKeyCode =
       NonLocatedToLocatedKeypadKeyboardCode(event.key_code(), event.code());
   webkit_event.nativeKeyCode =
       KeycodeConverter::DomCodeToNativeKeycode(event.code());
   webkit_event.domCode = static_cast<int>(event.code());
@@ skipping 327 matching lines @@
   webkit_event.tiltX = roundf(event.pointer_details().tilt_x);
   webkit_event.tiltY = roundf(event.pointer_details().tilt_y);
   webkit_event.force = event.pointer_details().force;
   webkit_event.pointerType =
       EventPointerTypeToWebPointerType(event.pointer_details().pointer_type);
 
   return webkit_event;
 }
 
 }  // namespace ui