Add blink::WebInputEvent::IsPinchGestureEventType().

ui/web_dialogs/web_dialog_web_contents_delegate.cc

Index: ui/web_dialogs/web_dialog_web_contents_delegate.cc
diff --git a/ui/web_dialogs/web_dialog_web_contents_delegate.cc b/ui/web_dialogs/web_dialog_web_contents_delegate.cc
index ee847442d95069dbb83815c48869dd50651c6dc6..59f1658492f579d63294625a7400649e3af214d5 100644
--- a/ui/web_dialogs/web_dialog_web_contents_delegate.cc
+++ b/ui/web_dialogs/web_dialog_web_contents_delegate.cc
@@ -60,9 +60,7 @@ bool WebDialogWebContentsDelegate::PreHandleGestureEvent(
     WebContents* source,
     const blink::WebGestureEvent& event) {
   // Disable pinch zooming.
-  return event.GetType() == blink::WebGestureEvent::kGesturePinchBegin ||
-         event.GetType() == blink::WebGestureEvent::kGesturePinchUpdate ||
-         event.GetType() == blink::WebGestureEvent::kGesturePinchEnd;
+  return blink::WebInputEvent::IsPinchGestureEventType(event.GetType());
 }
 
 }  // namespace ui