Fix mouse wheel events processing.

ui/views/test/event_generator_delegate_mac.mm

 // 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.
 
 #import <Cocoa/Cocoa.h>
 #include <stddef.h>
 
 #import "base/mac/scoped_nsobject.h"
 #import "base/mac/scoped_objc_class_swizzler.h"
 #include "base/macros.h"
@@ skipping 199 matching lines @@
                             location:point
                        modifierFlags:modifiers
                            timestamp:0
                         windowNumber:[window windowNumber]
                              context:nil
                          eventNumber:0
                           clickCount:click_count
                             pressure:1.0];
 }
 
+NSEvent* CreateMouseWheelEventInWindow(NSWindow* window,
+                                       const ui::MouseEvent* mouse_event) {
+  DCHECK_EQ(mouse_event->type(), ui::ET_MOUSEWHEEL);
+  const ui::MouseWheelEvent* mouse_wheel_event =
+      mouse_event->AsMouseWheelEvent();
+  return cocoa_test_event_utils::TestScrollEvent(
+      ConvertRootPointToTarget(window, mouse_wheel_event->location()), window,
+      mouse_wheel_event->x_offset(), mouse_wheel_event->y_offset(), false,
+      NSEventPhaseNone, NSEventPhaseNone);
+}
+
 // Implementation of ui::test::EventGeneratorDelegate for Mac. Everything
 // defined inline is just a stub. Interesting overrides are defined below the
 // class.
 class EventGeneratorDelegateMac : public ui::EventTarget,
                                   public ui::EventSource,
                                   public ui::EventHandler,
                                   public ui::EventProcessor,
                                   public ui::EventTargeter,
                                   public ui::test::EventGeneratorDelegate {
  public:
@@ skipping 112 matching lines @@
   ui::test::EventGenerator::default_delegate = nullptr;
 }
 
 std::unique_ptr<ui::EventTargetIterator>
 EventGeneratorDelegateMac::GetChildIterator() const {
   // Return nullptr to dispatch all events to the result of GetRootTarget().
   return nullptr;
 }
 
 void EventGeneratorDelegateMac::OnMouseEvent(ui::MouseEvent* event) {
-  NSEvent* ns_event = CreateMouseEventInWindow(window_,
-                                               event->type(),
-                                               event->location(),
-                                               event->changed_button_flags());
+  NSEvent* ns_event =
+      event->type() == ui::ET_MOUSEWHEEL
+          ? CreateMouseWheelEventInWindow(window_, event)
+          : CreateMouseEventInWindow(window_, event->type(), event->location(),
+                                     event->changed_button_flags());
+
   if (owner_->targeting_application())
     [NSApp sendEvent:ns_event];
   else
     EmulateSendEvent(window_, ns_event);
 }
 
 void EventGeneratorDelegateMac::OnKeyEvent(ui::KeyEvent* event) {
   NSUInteger modifiers = EventFlagsToModifiers(event->flags());
   NSEvent* ns_event = cocoa_test_event_utils::SynthesizeKeyEvent(
       window_, event->type() == ui::ET_KEY_PRESSED, event->key_code(),
@@ skipping 125 matching lines @@
 - (NSEvent*)currentEvent {
   if (g_current_event)
     return g_current_event;
 
   // Find the original implementation and invoke it.
   IMP original = EventGeneratorDelegateMac::GetInstance()->CurrentEventMethod();
   return original(self, _cmd);
 }
 
 @end