Remove some confusing code from ToplevelWindowEventHandler::HandleMousePressed()

ui/events/event_utils.h

 // Copyright (c) 2012 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.
 
 #ifndef UI_EVENTS_EVENT_UTILS_H_
 #define UI_EVENTS_EVENT_UTILS_H_
 
 #include "base/event_types.h"
 #include "ui/events/event_constants.h"
 #include "ui/events/keycodes/keyboard_codes.h"
@@ skipping 140 matching lines @@
 // Returns true if |message| identifies a mouse event that was generated as the
 // result of a touch event.
 EVENTS_EXPORT bool IsMouseEventFromTouch(UINT message);
 
 // Converts scan code and lParam each other.  The scan code
 // representing an extended key contains 0xE000 bits.
 EVENTS_EXPORT uint16 GetScanCodeFromLParam(LPARAM lParam);
 EVENTS_EXPORT LPARAM GetLParamFromScanCode(uint16 scan_code);
 #endif
 
-// Returns true if default post-target handling was canceled for |event| after
-// its dispatch to its target.
-EVENTS_EXPORT bool EventCanceledDefaultHandling(const Event& event);
-
 // Registers a custom event type.
 EVENTS_EXPORT int RegisterCustomEventType();
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_EVENT_UTILS_H_