touchui: Convert XI2 MT tracking id to slot id for gesture recognizer

views/touchui/touch_factory.cc

Index: views/touchui/touch_factory.cc
diff --git a/views/touchui/touch_factory.cc b/views/touchui/touch_factory.cc
index e644bca965c1e70b998614086f0bb8525d6ff955..d16eeaadba80c1966812b6a6f80281bf1f4d59e8 100644
--- a/views/touchui/touch_factory.cc
+++ b/views/touchui/touch_factory.cc
@@ -134,10 +134,12 @@ TouchFactory::TouchFactory()
       keep_mouse_cursor_(false),
       cursor_timer_(),
       pointer_device_lookup_(),
+      touch_device_list_(),
 #if defined(USE_XI2_MT)
-      touch_device_list_() {
+      min_available_slot_(0),
+      slots_used_(),
+      tracking_id_map_() {
 #else
-      touch_device_list_(),
       slots_used_() {
 #endif
 #if defined(TOUCH_UI)
@@ -327,7 +329,46 @@ bool TouchFactory::IsTouchDevice(unsigned deviceid) const {
       touch_device_lookup_[deviceid] : false;
 }
 
-#if !defined(USE_XI2_MT)
+#if defined(USE_XI2_MT)
+int TouchFactory::GetSlotForTrackingID(uint32 tracking_id) {
+  TrackingIdMap::iterator itr = tracking_id_map_.find(tracking_id);
+  if (itr != tracking_id_map_.end())
+    return itr->second;
+
+  int slot = min_available_slot_;
+  if (slot == kMaxTouchPoints) {
+    LOG(ERROR) << "Could not find available slot for touch point";
+    return 0;
+  }
+  SetSlotUsed(slot, true);
+  tracking_id_map_.insert(std::make_pair(tracking_id, slot));
+
+  // Updates the minium available slot ID

[Daniel Kurtz, 2011/09/26 08:29:17]

  while (++min_available_slot_ < kMaxTouchPoints &&
         IsSlotUsed(min_available_slot_))
    continue;

[ningxin.hu, 2011/09/26 15:44:06]

Good! I will merge the code. Thanks.

+  min_available_slot_++;
+  while (min_available_slot_ < kMaxTouchPoints)
+  {
+    if (!IsSlotUsed(min_available_slot_))
+      break;
+    min_available_slot_++;
+  }
+
+  return slot;
+}
+
+void TouchFactory::ReleaseSlotForTrackingID(uint32 tracking_id) {
+  TrackingIdMap::iterator itr = tracking_id_map_.find(tracking_id);
+  if (itr != tracking_id_map_.end()) {
+    int slot = itr->second;
+    SetSlotUsed(slot, false);
+    tracking_id_map_.erase(itr);
+    if (slot < min_available_slot_)
+      min_available_slot_ = slot;
+  } else {
+    NOTREACHED() << "Cannot find slot mapping to tracking ID " << tracking_id;
+  }
+}
+#endif
+
 bool TouchFactory::IsSlotUsed(int slot) const {
   CHECK_LT(slot, kMaxTouchPoints);
   return slots_used_[slot];
@@ -337,7 +378,6 @@ void TouchFactory::SetSlotUsed(int slot, bool used) {
   CHECK_LT(slot, kMaxTouchPoints);
   slots_used_[slot] = used;
 }
-#endif
 
 bool TouchFactory::GrabTouchDevices(Display* display, ::Window window) {
 #if defined(TOUCH_UI)