Do not increase the pointer id when type is eraser

third_party/WebKit/Source/core/events/PointerEventFactory.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/events/PointerEventFactory.h"
 
 #include "core/frame/FrameView.h"
 #include "platform/geometry/FloatSize.h"
 
 namespace blink {
 
 namespace {
 
 inline int ToInt(WebPointerProperties::PointerType t) {
   return static_cast<int>(t);
 }
 
 const char* PointerTypeNameForWebPointPointerType(
     WebPointerProperties::PointerType type) {
+  // TODO(mustaq): Fix when the spec starts supporting hovering erasers.
   switch (type) {
     case WebPointerProperties::PointerType::kUnknown:
       return "";
     case WebPointerProperties::PointerType::kTouch:
       return "touch";
     case WebPointerProperties::PointerType::kPen:
-    case WebPointerProperties::PointerType::kEraser:
-      // TODO(mustaq): Fix when the spec starts supporting hovering erasers.
       return "pen";
     case WebPointerProperties::PointerType::kMouse:
       return "mouse";
+    default:
+      NOTREACHED();
+      return "";
   }
-  NOTREACHED();
-  return "";
 }
 
 const AtomicString& PointerEventNameForMouseEventName(
     const AtomicString& mouse_event_name) {
 #define RETURN_CORRESPONDING_PE_NAME(eventSuffix)               \
   if (mouse_event_name == EventTypeNames::mouse##eventSuffix) { \
     return EventTypeNames::pointer##eventSuffix;                \
   }
 
   RETURN_CORRESPONDING_PE_NAME(down);
@@ skipping 137 matching lines @@
 
 const int PointerEventFactory::kInvalidId = 0;
 
 // Mouse id is 1 to behave the same as MS Edge for compatibility reasons.
 const int PointerEventFactory::kMouseId = 1;
 
 void PointerEventFactory::SetIdTypeButtons(
     PointerEventInit& pointer_event_init,
     const WebPointerProperties& pointer_properties,
     unsigned buttons) {
-  const WebPointerProperties::PointerType pointer_type =
+  WebPointerProperties::PointerType pointer_type =
       pointer_properties.pointer_type;
-  const IncomingId incoming_id(pointer_type, pointer_properties.id);
-  int pointer_id = AddIdAndActiveButtons(incoming_id, buttons != 0);
-
   // Tweak the |buttons| to reflect pen eraser mode only if the pen is in
   // active buttons state w/o even considering the eraser button.
   // TODO(mustaq): Fix when the spec starts supporting hovering erasers.
-  if (pointer_type == WebPointerProperties::PointerType::kEraser &&
-      buttons != 0) {
-    buttons |= static_cast<unsigned>(WebPointerProperties::Buttons::kEraser);
-    buttons &= ~static_cast<unsigned>(WebPointerProperties::Buttons::kLeft);
+  if (pointer_type == WebPointerProperties::PointerType::kEraser) {
+    if (buttons != 0) {
+      buttons |= static_cast<unsigned>(WebPointerProperties::Buttons::kEraser);
+      buttons &= ~static_cast<unsigned>(WebPointerProperties::Buttons::kLeft);
+    }
+    pointer_type = WebPointerProperties::PointerType::kPen;
   }
   pointer_event_init.setButtons(buttons);
 
+  const IncomingId incoming_id(pointer_type, pointer_properties.id);
+  int pointer_id = AddIdAndActiveButtons(incoming_id, buttons != 0);
   pointer_event_init.setPointerId(pointer_id);
   pointer_event_init.setPointerType(
       PointerTypeNameForWebPointPointerType(pointer_type));
   pointer_event_init.setIsPrimary(IsPrimary(pointer_id));
 }
 
 void PointerEventFactory::SetEventSpecificFields(
     PointerEventInit& pointer_event_init,
     const AtomicString& type) {
   pointer_event_init.setBubbles(type != EventTypeNames::pointerenter &&
@@ skipping 292 matching lines @@
   IncomingId p = pointer_id_mapping_.at(mapped_id).incoming_id;
   int type_int = p.PointerTypeInt();
   pointer_id_mapping_.erase(mapped_id);
   pointer_incoming_id_mapping_.erase(p);
   if (primary_id_[type_int] == mapped_id)
     primary_id_[type_int] = PointerEventFactory::kInvalidId;
   id_count_[type_int]--;
   return true;
 }
 
+// This function does not work with pointer type of eraser, because we save
+// them as pen type in the pointer id map.
 Vector<int> PointerEventFactory::GetPointerIdsOfType(
     WebPointerProperties::PointerType pointer_type) const {
   Vector<int> mapped_ids;
 
   for (auto iter = pointer_id_mapping_.begin();
        iter != pointer_id_mapping_.end(); ++iter) {
     int mapped_id = iter->key;
     if (iter->value.incoming_id.GetPointerType() == pointer_type)
       mapped_ids.push_back(mapped_id);
   }
@@ skipping 31 matching lines @@
     const WebPointerProperties& properties) const {
   if (properties.pointer_type == WebPointerProperties::PointerType::kMouse)
     return PointerEventFactory::kMouseId;
   IncomingId id(properties.pointer_type, properties.id);
   if (pointer_incoming_id_mapping_.Contains(id))
     return pointer_incoming_id_mapping_.at(id);
   return PointerEventFactory::kInvalidId;
 }
 
 }  // namespace blink