Support NSFlagsChanged in ui::EventFromNative.

ui/events/test/cocoa_test_event_utils.h

 // Copyright 2014 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_TEST_COCOA_TEST_EVENT_UTILS_H_
 #define UI_EVENTS_TEST_COCOA_TEST_EVENT_UTILS_H_
 
 #import <Cocoa/Cocoa.h>
 #import <objc/objc-class.h>
 
@@ skipping 56 matching lines @@
 
 // Returns a key event with the given type and modifier flags.
 NSEvent* KeyEventWithType(NSEventType event_type, NSUInteger modifiers);
 
 // Returns a key event with the given key code, type, and modifier flags.
 NSEvent* KeyEventWithKeyCode(unsigned short key_code,
                              unichar c,
                              NSEventType event_type,
                              NSUInteger modifiers);
 
+// Returns a key event for pressing or releasing a modifier key (aka
+// NSFlagsChanged). For example |key_code| == kVK_Shift with |modifiers| &
+// NSShiftKeyMask == true means Shift is pressed and |key_code| == kVK_Shift

[tapted, 2016/10/25 06:55:10]

nit: `|modifiers| & NSShiftKeyMask == true` -> `(|modifiers| & NSShiftKeyMask)
!= 0`

[alshabalin, 2016/10/28 19:58:14]

Done.

+// with |modifiers| & NSShiftKeyMask == false means Shift is released.

[tapted, 2016/10/25 06:55:10]

`|modifiers| & NSShiftKeyMask == false` -> `(|modifiers| & NSShiftKeyMask) == 0`

[alshabalin, 2016/10/28 19:58:14]

Done.

+NSEvent* KeyEventWithModifierOnly(unsigned short key_code,
+                                  NSUInteger modifiers);
+
 // Returns a mouse enter event.
 NSEvent* EnterEvent();
 
 // Returns a mouse exit event.
 NSEvent* ExitEvent();
 
 // Return an "other" event with the given type.
 NSEvent* OtherEventWithType(NSEventType event_type);
 
 // Time interval since system startup. Tests shouldn't rely on this.
 NSTimeInterval TimeIntervalSinceSystemStartup();
 
 // Creates a key event in a particular window.
 NSEvent* SynthesizeKeyEvent(NSWindow* window,
                             bool keyDown,
                             ui::KeyboardCode keycode,
                             NSUInteger flags,
                             ui::DomKey dom_key = ui::DomKey::NONE);
 
 }  // namespace cocoa_test_event_utils
 
 #endif  // UI_EVENTS_TEST_COCOA_TEST_EVENT_UTILS_H_