Fix compile error for MacOSX10.11.sdk using static_cast<CGEventFlags>

ui/events/test/cocoa_test_event_utils.mm

Index: ui/events/test/cocoa_test_event_utils.mm
diff --git a/ui/events/test/cocoa_test_event_utils.mm b/ui/events/test/cocoa_test_event_utils.mm
index b225710adc61099936f04e5b7c03d0714c0481cb..7e1b2b454cafe07d3f6b6e2252a228c707c10aea 100644
--- a/ui/events/test/cocoa_test_event_utils.mm
+++ b/ui/events/test/cocoa_test_event_utils.mm
@@ -153,7 +153,7 @@ NSEvent* TestScrollEvent(NSPoint window_point,
 
   // Always set event flags, otherwise +[NSEvent eventWithCGEvent:] populates
   // flags from current keyboard state which can make tests flaky.
-  CGEventSetFlags(scroll, 0);
+  CGEventSetFlags(scroll, static_cast<CGEventFlags>(kCGEventNull));

[tapted, 2016/09/27 06:40:16]

kCGEventNull -> 0

kCGEventNull is a CGEventType (32-bit enum) not a CGEventFlags (64-bit bitmask)
- bizarrely the new SDK doesn't provide a constant for 0

[tikuta, 2016/09/27 06:49:03]

Done.

 
   if (has_precise_deltas) {
     // kCGScrollWheelEventIsContinuous is -[NSEvent hasPreciseScrollingDeltas].