use enum to specify deviceSource for fling animation.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index a2bdcb134cb86b2e2ebce697c20e809c1f1876e0..de2cc4ba46af1cd1ac4d1337d5b216c3be60de2a 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -1212,7 +1212,7 @@ bool WebContentsImpl::HandleGestureEvent(
   // Some platforms (eg. Mac) send GesturePinch events for trackpad pinch-zoom.
   // Use them to implement browser zoom, as for HandleWheelEvent above.
   if (event.type == blink::WebInputEvent::GesturePinchUpdate &&
-      event.sourceDevice == blink::WebGestureEvent::Touchpad) {
+      event.sourceDevice == blink::WebGestureDeviceTouchpad) {
     // The scale difference necessary to trigger a zoom action. Derived from
     // experimentation to find a value that feels reasonable.
     const float kZoomStepValue = 0.6f;