Initial browser-side implementation for touch-action

content/browser/renderer_host/input/immediate_input_router.cc

Index: content/browser/renderer_host/input/immediate_input_router.cc
diff --git a/content/browser/renderer_host/input/immediate_input_router.cc b/content/browser/renderer_host/input/immediate_input_router.cc
index 444678fda27412acab88c21914cdf0a8ff814935..a21ce452c905783bbd097d256aeca936b45c4e7d 100644
--- a/content/browser/renderer_host/input/immediate_input_router.cc
+++ b/content/browser/renderer_host/input/immediate_input_router.cc
@@ -23,6 +23,7 @@
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/common/content_switches.h"
+#include "content/public/common/touch_action.h"
 #include "ipc/ipc_sender.h"
 #include "ui/events/event.h"
 #include "ui/events/keycodes/keyboard_codes.h"
@@ -85,6 +86,8 @@ ImmediateInputRouter::ImmediateInputRouter(IPC::Sender* sender,
       mouse_move_pending_(false),
       mouse_wheel_pending_(false),
       has_touch_handler_(false),
+      drop_scroll_gesture_events_(false),
+      allowed_touch_action_(content::TOUCH_ACTION_AUTO),
       current_ack_source_(ACK_SOURCE_NONE),
       touch_event_queue_(new TouchEventQueue(this)),
       gesture_event_filter_(new GestureEventFilter(this, this)) {
@@ -180,7 +183,8 @@ void ImmediateInputRouter::SendKeyboardEvent(
 
 void ImmediateInputRouter::SendGestureEvent(
     const GestureEventWithLatencyInfo& gesture_event) {
-  HandleGestureScroll(gesture_event);
+  if (FilterTouchAction(gesture_event))
+    return;
 
   if (!IsInOverscrollGesture() &&
       !gesture_event_filter_->ShouldForward(gesture_event)) {
@@ -227,7 +231,8 @@ void ImmediateInputRouter::SendTouchEventImmediately(
 
 void ImmediateInputRouter::SendGestureEventImmediately(
     const GestureEventWithLatencyInfo& gesture_event) {
-  HandleGestureScroll(gesture_event);
+  if (FilterTouchAction(gesture_event))
+    return;
   FilterAndSendWebInputEvent(gesture_event.event, gesture_event.latency, false);
 }
 
@@ -255,6 +260,8 @@ bool ImmediateInputRouter::OnMessageReceived(const IPC::Message& message) {
     IPC_MESSAGE_HANDLER(ViewHostMsg_SelectRange_ACK, OnSelectRangeAck)
     IPC_MESSAGE_HANDLER(ViewHostMsg_HasTouchEventHandlers,
                         OnHasTouchEventHandlers)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_SetTouchAction,
+                        OnSetTouchAction)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
@@ -462,6 +469,23 @@ void ImmediateInputRouter::OnHasTouchEventHandlers(bool has_handlers) {
   client_->OnHasTouchEventHandlers(has_handlers);
 }
 
+void ImmediateInputRouter::OnSetTouchAction(
+    int touch_id,
+    content::TouchAction touchAction)
+{
+  // Don't process touch-action messages for synthetic touches we know
+  // nothing about.
+  if (!touch_event_queue_->IsTouchStartPendingAck(touch_id))
+    return;
+
+  // For multiple fingers, we take the intersection of the touch actions for
+  // all fingers that have gone down during this action.
+  // TODO(rbyers): Get some agreed upon multi-finger semantic for touch-action
+  // included in the pointer events specification. crbug.com/241964
+  if (touchAction == content::TOUCH_ACTION_NONE)
+    allowed_touch_action_ = content::TOUCH_ACTION_NONE;
+}
+
 void ImmediateInputRouter::ProcessInputEventAck(
     WebInputEvent::Type event_type,
     InputEventAckState ack_result,
@@ -591,9 +615,41 @@ void ImmediateInputRouter::ProcessAckForOverscroll(
       event, (INPUT_EVENT_ACK_STATE_CONSUMED == ack_result));
 }
 
-void ImmediateInputRouter::HandleGestureScroll(
+bool ImmediateInputRouter::FilterTouchAction(
     const GestureEventWithLatencyInfo& gesture_event) {
+
+  // Filter for allowable touch actions first (eg. before the TouchEventQueue
+  // can decide to send a touch cancel event).
+  // TODO: Does this belong in GestureEventFilter, even though the filtering
+  // happens at a different stage from the other filters there?
+  // TODO(rbyers): Add touch-action control over for pinch.  crbug.com/247566.
+  switch(gesture_event.event.type) {
+  case WebInputEvent::GestureScrollBegin:
+    if (allowed_touch_action_ == TOUCH_ACTION_NONE)
+      drop_scroll_gesture_events_ = true;
+    // FALL THROUGH
+  case WebInputEvent::GestureScrollUpdate:
+  case WebInputEvent::GestureScrollUpdateWithoutPropagation:
+    if (drop_scroll_gesture_events_)
+      return true;
+    break;
+
+  case WebInputEvent::GestureScrollEnd:
+  case WebInputEvent::GestureFlingStart:
+    allowed_touch_action_ = content::TOUCH_ACTION_AUTO;
+    if (drop_scroll_gesture_events_) {
+      drop_scroll_gesture_events_ = false;
+      return true;
+    }
+    break;
+
+  default:
+    break;
+  }
+
+  // This touch action is permitted, allow it to cancel in-progress touches.
   touch_event_queue_->OnGestureScrollEvent(gesture_event);
+  return false;
 }
 
 void ImmediateInputRouter::SimulateTouchGestureWithMouse(