Implement direction-specific touch-action values (chromium side).

content/browser/renderer_host/input/touch_action_filter.cc

Index: content/browser/renderer_host/input/touch_action_filter.cc
diff --git a/content/browser/renderer_host/input/touch_action_filter.cc b/content/browser/renderer_host/input/touch_action_filter.cc
index 1f1855df7ea59de6478281efe61abd61c423e350..17f7ef3019e01e9c845052522278b782523b8ac1 100644
--- a/content/browser/renderer_host/input/touch_action_filter.cc
+++ b/content/browser/renderer_host/input/touch_action_filter.cc
@@ -35,10 +35,12 @@ bool TouchActionFilter::FilterGestureEvent(WebGestureEvent* gesture_event) {
       if (drop_scroll_gesture_events_)
         return true;
       else {
-        if (allowed_touch_action_ == TOUCH_ACTION_PAN_X) {
+        if (allowed_touch_action_ & TOUCH_ACTION_PAN_X &&

[Rick Byers, 2015/05/07 20:37:37]

This is now sufficiently non-trivial that I think it deserves a comment.  Eg:
"Scrolls restricted to a specific axis shouldn't permit movement in the
perpendicular axis.".

I wrote this into the spec as "when scrolling is restricted to starting along a
single axis (eg. pan-y), the axis cannot be changed during the scroll".

[dtapuska, 2015/05/07 21:03:07]

Done.

+            !(allowed_touch_action_ & ~TOUCH_ACTION_PAN_X)) {
           gesture_event->data.scrollUpdate.deltaY = 0;
           gesture_event->data.scrollUpdate.velocityY = 0;
-        } else if (allowed_touch_action_ == TOUCH_ACTION_PAN_Y) {
+        } else if (allowed_touch_action_ & TOUCH_ACTION_PAN_Y &&
+                   !(allowed_touch_action_ & ~TOUCH_ACTION_PAN_Y)) {
           gesture_event->data.scrollUpdate.deltaX = 0;
           gesture_event->data.scrollUpdate.velocityX = 0;
         }
@@ -52,10 +54,13 @@ bool TouchActionFilter::FilterGestureEvent(WebGestureEvent* gesture_event) {
       DCHECK(gesture_event->data.flingStart.velocityX ||
              gesture_event->data.flingStart.velocityY);
       if (!drop_scroll_gesture_events_) {
-        if (allowed_touch_action_ == TOUCH_ACTION_PAN_X)
+        if (allowed_touch_action_ & TOUCH_ACTION_PAN_X &&
+            !(allowed_touch_action_ & ~TOUCH_ACTION_PAN_X)) {
           gesture_event->data.flingStart.velocityY = 0;
-        if (allowed_touch_action_ == TOUCH_ACTION_PAN_Y)
+        } else if (allowed_touch_action_ & TOUCH_ACTION_PAN_Y &&
+                   !(allowed_touch_action_ & ~TOUCH_ACTION_PAN_Y)) {
           gesture_event->data.flingStart.velocityX = 0;
+        }
         // As the renderer expects a scroll-ending event, but does not expect a
         // zero-velocity fling, convert the now zero-velocity fling accordingly.
         if (!gesture_event->data.flingStart.velocityX &&
@@ -184,9 +189,31 @@ bool TouchActionFilter::ShouldSuppressScroll(
   // Determine the primary initial axis of the scroll, and check whether
   // panning along that axis is permitted.
   if (fabs(gesture_event.data.scrollBegin.deltaXHint) >
-      fabs(gesture_event.data.scrollBegin.deltaYHint))
-    return !(allowed_touch_action_ & TOUCH_ACTION_PAN_X);
-  return !(allowed_touch_action_ & TOUCH_ACTION_PAN_Y);
+      fabs(gesture_event.data.scrollBegin.deltaYHint)) {
+    if ((allowed_touch_action_ & TOUCH_ACTION_PAN_X) == TOUCH_ACTION_PAN_X) {

[Rick Byers, 2015/05/07 20:37:37]

nit: You could remove this case (it's covered by the combination of the below
two), right?

[dtapuska, 2015/05/07 21:03:07]

Done.

+      return false;
+    } else if (gesture_event.data.scrollBegin.deltaXHint > 0 &&

[dtapuska, 2015/05/07 19:06:30]

Please check this logic..

I originally wrote it as < 0 for this line (and the converse for the pan_right).
And similar changes on the pan-down/pan-up.

But it seemed to move in the incorrect direction as to what I thought it would
be. I can show you the implementation if you like.

[Rick Byers, 2015/05/07 20:37:37]

Yes, this is correct but I've got a bug in the spec in this regard (confusion
motion of the finger and motion of the content).  Will update and cc you on
public-pointer-events thread.

[dtapuska, 2015/05/07 21:03:07]

Acknowledged.

+               allowed_touch_action_ & TOUCH_ACTION_PAN_LEFT) {
+      return false;
+    } else if (gesture_event.data.scrollBegin.deltaXHint < 0 &&
+               allowed_touch_action_ & TOUCH_ACTION_PAN_RIGHT) {
+      return false;
+    } else {
+      return true;
+    }
+  } else {
+    if ((allowed_touch_action_ & TOUCH_ACTION_PAN_Y) == TOUCH_ACTION_PAN_Y) {
+      return false;

[Rick Byers, 2015/05/07 20:37:37]

ditto

[dtapuska, 2015/05/07 21:03:07]

Done.

+    } else if (gesture_event.data.scrollBegin.deltaYHint > 0 &&
+               allowed_touch_action_ & TOUCH_ACTION_PAN_UP) {
+      return false;
+    } else if (gesture_event.data.scrollBegin.deltaYHint < 0 &&
+               allowed_touch_action_ & TOUCH_ACTION_PAN_DOWN) {
+      return false;
+    } else {
+      return true;
+    }
+  }
 }
 
 TouchAction TouchActionFilter::Intersect(TouchAction ta1, TouchAction ta2) {