use enum to specify deviceSource for fling animation.

content/browser/web_contents/web_contents_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 1194 matching lines @@
 bool WebContentsImpl::PreHandleGestureEvent(
     const blink::WebGestureEvent& event) {
   return delegate_ && delegate_->PreHandleGestureEvent(this, event);
 }
 
 bool WebContentsImpl::HandleGestureEvent(
     const blink::WebGestureEvent& event) {
   // 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;
 
     // Find the (absolute) thresholds on either side of the current zoom factor,
     // then convert those to actual numbers to trigger a zoom in or out.
     // This logic deliberately makes the range around the starting zoom value
     // for the gesture twice as large as the other ranges (i.e., the notches are
     // at ..., -3*step, -2*step, -step, step, 2*step, 3*step, ... but not at 0)
     // so that it's easier to get back to your starting point than it is to
@@ skipping 2845 matching lines @@
 
 void WebContentsImpl::OnPreferredSizeChanged(const gfx::Size& old_size) {
   if (!delegate_)
     return;
   const gfx::Size new_size = GetPreferredSize();
   if (new_size != old_size)
     delegate_->UpdatePreferredSize(this, new_size);
 }
 
 }  // namespace content