Fixed two-finger pan filtering with 'touch-action: pan-x pan-y'.

content/common/input/synthetic_web_input_event_builders.cc

Index: content/common/input/synthetic_web_input_event_builders.cc
diff --git a/content/common/input/synthetic_web_input_event_builders.cc b/content/common/input/synthetic_web_input_event_builders.cc
index 6533863a2b1bd9f1caca2e6d332910ab8d35bf11..9d1b751c5911b76d9e4e05b18b30adb52c1d312f 100644
--- a/content/common/input/synthetic_web_input_event_builders.cc
+++ b/content/common/input/synthetic_web_input_event_builders.cc
@@ -117,11 +117,13 @@ WebGestureEvent SyntheticWebGestureEventBuilder::Build(
 WebGestureEvent SyntheticWebGestureEventBuilder::BuildScrollBegin(
     float dx_hint,
     float dy_hint,
-    blink::WebGestureDevice source_device) {
+    blink::WebGestureDevice source_device,
+    int pointer_count) {
   WebGestureEvent result =
       Build(WebInputEvent::GestureScrollBegin, source_device);
   result.data.scrollBegin.deltaXHint = dx_hint;
   result.data.scrollBegin.deltaYHint = dy_hint;
+  result.data.scrollBegin.pointerCount = pointer_count;
   return result;
 }