Mac: Consolidate test mouse event generation into a single codepath.

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 24c948f33d40ee652ab39fef7a705e7223f272b8..9843be6f2f874b82151183127640b0644bb92b95 100644
--- a/ui/events/test/cocoa_test_event_utils.h
+++ b/ui/events/test/cocoa_test_event_utils.h
@@ -50,6 +50,12 @@ std::pair<NSEvent*, NSEvent*> MouseClickInView(NSView* view,
 std::pair<NSEvent*, NSEvent*> RightMouseClickInView(NSView* view,
                                                     NSUInteger clickCount);
 
+NSEvent* TestMouseEvent(NSPoint window_point,
+                        NSEventType type,
+                        NSWindow* window,
+                        NSUInteger modifiers,
+                        NSUInteger clickCount);
+
 // 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