Postpone rail application for touch scrolling - chrome side.

content/renderer/input/input_handler_proxy.cc

Index: content/renderer/input/input_handler_proxy.cc
diff --git a/content/renderer/input/input_handler_proxy.cc b/content/renderer/input/input_handler_proxy.cc
index f714ef1f3d956678b8ba0b3cd744f85715a142a7..1fc8a1dad061db0318e274620840f53448747a03 100644
--- a/content/renderer/input/input_handler_proxy.cc
+++ b/content/renderer/input/input_handler_proxy.cc
@@ -456,8 +456,18 @@ InputHandlerProxy::HandleGestureScrollUpdate(
     return DID_NOT_HANDLE;
 
   gfx::Point scroll_point(gesture_event.x, gesture_event.y);
-  gfx::Vector2dF scroll_delta(-gesture_event.data.scrollUpdate.deltaX,
-                              -gesture_event.data.scrollUpdate.deltaY);
+
+  // TODO(tdresser): The rail information should be pushed down into
+  // InputHandler.

[ccameron, 2015/04/01 17:20:25]

Oh, crap, I didn't do my TODO for this that I'd promised.

I'll do that right now, and then you can just pass the rails mode into the
InputHandler.

[tdresser, 2015/04/01 17:22:45]

Sounds good, thanks.

+  const float dx = gesture_event.data.scrollUpdate.deltaX;
+  const float dy = gesture_event.data.scrollUpdate.deltaY;
+  const WebInputEvent::RailsMode railsMode =
+      gesture_event.data.scrollUpdate.railsMode;
+
+  gfx::Vector2dF scroll_delta(
+      railsMode != WebInputEvent::RailsModeVertical ? -dx : 0,
+      railsMode != WebInputEvent::RailsModeHorizontal ? -dy : 0);
+
   cc::InputHandlerScrollResult scroll_result = input_handler_->ScrollBy(
       scroll_point, scroll_delta);
   HandleOverscroll(scroll_point, scroll_result);
@@ -501,9 +511,21 @@ InputHandlerProxy::EventDisposition InputHandlerProxy::HandleGestureFlingStart(
       if (gesture_event.sourceDevice == blink::WebGestureDeviceTouchpad)
         input_handler_->ScrollEnd();
 
-      const float vx = gesture_event.data.flingStart.velocityX;
-      const float vy = gesture_event.data.flingStart.velocityY;
-      current_fling_velocity_ = gfx::Vector2dF(vx, vy);
+      // TODO(tdresser): The rail information should be pushed down into
+      // InputHandler.
+      const WebInputEvent::RailsMode railsMode =
+          gesture_event.data.flingStart.railsMode;
+
+      float vx = railsMode != WebInputEvent::RailsModeVertical
+                     ? gesture_event.data.flingStart.velocityX
+                     : 0;
+      float vy = railsMode != WebInputEvent::RailsModeHorizontal
+                     ? gesture_event.data.flingStart.velocityY
+                     : 0;
+
+      current_fling_velocity_.set_x(vx);
+      current_fling_velocity_.set_y(vy);
+
       DCHECK(!current_fling_velocity_.IsZero());
       fling_curve_.reset(client_->CreateFlingAnimationCurve(
           gesture_event.sourceDevice,