Revert of Don't treat first touch move differently from future touch moves

content/browser/renderer_host/input/touch_event_queue.cc

Index: content/browser/renderer_host/input/touch_event_queue.cc
diff --git a/content/browser/renderer_host/input/touch_event_queue.cc b/content/browser/renderer_host/input/touch_event_queue.cc
index db4fa9117906215b361ca482cdc7bfbd12cabd12..bbac01c3ebff51081f112419068c5525a4bad5cf 100644
--- a/content/browser/renderer_host/input/touch_event_queue.cc
+++ b/content/browser/renderer_host/input/touch_event_queue.cc
@@ -349,8 +349,7 @@
       send_touch_events_async_(false),
       needs_async_touchmove_for_outer_slop_region_(false),
       last_sent_touch_timestamp_sec_(0),
-  touch_scrolling_mode_(config.touch_scrolling_mode),
-  seen_scroll_update_this_sequence_(false) {
+      touch_scrolling_mode_(config.touch_scrolling_mode) {
   DCHECK(client);
   if (ack_timeout_enabled_) {
     timeout_handler_.reset(
@@ -535,37 +534,31 @@
 
 void TouchEventQueue::OnGestureScrollEvent(
     const GestureEventWithLatencyInfo& gesture_event) {
-  if (gesture_event.event.type == blink::WebInputEvent::GestureScrollBegin) {
-    seen_scroll_update_this_sequence_ = false;
-
+  if (gesture_event.event.type != blink::WebInputEvent::GestureScrollBegin)
+    return;
+
+  if (touch_filtering_state_ != DROP_ALL_TOUCHES &&
+      touch_filtering_state_ != DROP_TOUCHES_IN_SEQUENCE) {
+    DCHECK(!touchmove_slop_suppressor_->suppressing_touchmoves())
+        << "The renderer should be offered a touchmove before scrolling begins";
+  }
+
+  if (touch_scrolling_mode_ == TOUCH_SCROLLING_MODE_ASYNC_TOUCHMOVE) {
     if (touch_filtering_state_ != DROP_ALL_TOUCHES &&
         touch_filtering_state_ != DROP_TOUCHES_IN_SEQUENCE) {
-      DCHECK(!touchmove_slop_suppressor_->suppressing_touchmoves())
-          << "The renderer should be offered a touchmove before scrolling "
-             "begins";
-    }
-
-    if (touch_scrolling_mode_ == TOUCH_SCROLLING_MODE_ASYNC_TOUCHMOVE &&
-        touch_filtering_state_ != DROP_ALL_TOUCHES &&
-        touch_filtering_state_ != DROP_TOUCHES_IN_SEQUENCE &&
-        (touch_ack_states_.empty() ||
-         AllTouchAckStatesHaveState(
-             INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS))) {
       // If no touch points have a consumer, prevent all subsequent touch events
       // received during the scroll from reaching the renderer. This ensures
       // that the first touchstart the renderer sees in any given sequence can
       // always be preventDefault'ed (cancelable == true).
       // TODO(jdduke): Revisit if touchstarts during scroll are made cancelable.
-      touch_filtering_state_ = DROP_TOUCHES_IN_SEQUENCE;
-    }
-    return;
-  }
-
-  if (gesture_event.event.type != blink::WebInputEvent::GestureScrollUpdate ||
-      seen_scroll_update_this_sequence_)
-    return;
-
-  if (touch_scrolling_mode_ == TOUCH_SCROLLING_MODE_ASYNC_TOUCHMOVE) {
+      if (touch_ack_states_.empty() ||
+          AllTouchAckStatesHaveState(
+              INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS)) {
+        touch_filtering_state_ = DROP_TOUCHES_IN_SEQUENCE;
+        return;
+      }
+    }
+
     pending_async_touchmove_.reset();
     send_touch_events_async_ = true;
     needs_async_touchmove_for_outer_slop_region_ = true;