MacViews: Send Mac scrollWheel NSEvents as ui::ET_SCROLL (ui::ScrollEvent).

ui/events/test/cocoa_test_event_utils.h

Index: ui/events/test/cocoa_test_event_utils.h
diff --git a/ui/events/test/cocoa_test_event_utils.h b/ui/events/test/cocoa_test_event_utils.h
index 5e138878f7de54ce3bf64e6b6a499f5c0314408b..dbb538f570e98449f786c430a36127969d326aff 100644
--- a/ui/events/test/cocoa_test_event_utils.h
+++ b/ui/events/test/cocoa_test_event_utils.h
@@ -50,15 +50,17 @@ std::pair<NSEvent*, NSEvent*> MouseClickInView(NSView* view,
 std::pair<NSEvent*, NSEvent*> RightMouseClickInView(NSView* view,
                                                     NSUInteger clickCount);
 
-// Creates a test scroll event. Currently only events for a "real" mouse wheel
-// are supported (-hasPreciseScrollingDeltas is NO).  If |window| is nil,
-// |location| is assumed to be AppKit screen coordinates (origin in bottom left
-// of primary screen).
-// TODO(tapted): Add event phase arguments to support trackpad scrolls also.
+// Creates a test scroll event. |has_precise_deltas| determines the value of
+// -[NSEvent hasPreciseScrollingDeltas] - usually NO for a mouse wheel and YES
+// for a trackpad. If |window| is nil, |location| is assumed to be AppKit screen
+// coordinates (origin in bottom left of primary screen).
 NSEvent* TestScrollEvent(NSPoint location,
                          NSWindow* window,
                          CGFloat delta_x,
-                         CGFloat delta_y);
+                         CGFloat delta_y,
+                         bool has_precise_deltas,
+                         NSEventPhase event_phase,
+                         NSEventPhase momentum_phase);
 
 // Returns a key event with the given character.
 NSEvent* KeyEventWithCharacter(unichar c);