Redefined the bit WebTouchEvent.causesScrollingIfUncanceled.

third_party/WebKit/public/web/WebInputEvent.h

Index: third_party/WebKit/public/web/WebInputEvent.h
diff --git a/third_party/WebKit/public/web/WebInputEvent.h b/third_party/WebKit/public/web/WebInputEvent.h
index 92b6347a5996f609f49eb2870dee5ed97adb7134..75484c0ddd126e38d04ef3f682323e155d828372 100644
--- a/third_party/WebKit/public/web/WebInputEvent.h
+++ b/third_party/WebKit/public/web/WebInputEvent.h
@@ -582,12 +582,9 @@ public:
     // must wait for an ACK for this event. If false then no ACK IPC is expected.
     bool cancelable;
 
-    // Whether the event will produce scroll-inducing events if uncanceled. This
-    // will be true for touchmove events after the platform slop region has been
-    // exceeded and fling-generating touchend events. Note that this doesn't
-    // necessarily mean content will scroll, only that scroll events will be
-    // generated.
-    bool causesScrollingIfUncanceled;
+    // True for touchmove events after the platform slop region has been exceeded and
+    // fling-generating touchend events.

[Rick Byers, 2016/02/02 04:24:16]

Two questions that I think should be covered by this comment:
1) How does this behave for multi-finger scenarios?  Is it "true if ANY finger
has moved beyond the slop region"?
2) What about a touchend that occurs during a scroll but doesn't cause a fling
(due to 0 velocity)?

Also for a long drag where all the touch events are consumed, it seems odd to
have this be false for the touchend, even though it was true for the touchmoves.
 Or perhaps the "fling-generating" means prior to touch disposition gesture
filtering?

[mustaq, 2016/02/04 21:17:21]

Done.

+    bool movedBeyondSlopRegion;
 
     // A unique identifier for the touch event.
     uint32_t uniqueTouchEventId;
@@ -596,7 +593,7 @@ public:
         : WebInputEvent(sizeof(WebTouchEvent))
         , touchesLength(0)
         , cancelable(true)
-        , causesScrollingIfUncanceled(false)
+        , movedBeyondSlopRegion(false)
         , uniqueTouchEventId(0)
     {
     }