Identity the mouse pointer type from low-level events for Mac

content/browser/renderer_host/input/web_input_event_builders_mac.mm

 // Copyright 2015 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.
 
 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006-2009 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ skipping 645 matching lines @@
                     encoding:NSASCIIStringEncoding];
 
   result.timeStampSeconds = [event timestamp];
   result.isSystemKey = IsSystemKeyEvent(result);
 
   return result;
 }
 
 // WebMouseEvent --------------------------------------------------------------
 
-blink::WebMouseEvent WebMouseEventBuilder::Build(NSEvent* event, NSView* view) {
+blink::WebMouseEvent WebMouseEventBuilder::Build(
+    NSEvent* event,
+    NSView* view,
+    blink::WebPointerProperties::PointerType pointerType) {
   blink::WebMouseEvent result;
 
   result.clickCount = 0;
 
   switch ([event type]) {
     case NSMouseExited:
       result.type = blink::WebInputEvent::MouseLeave;
       result.button = blink::WebMouseEvent::ButtonNone;
       break;
     case NSLeftMouseDown:
@@ skipping 45 matching lines @@
     default:
       NOTIMPLEMENTED();
   }
 
   SetWebEventLocationFromEventInView(&result, event, view);
 
   result.modifiers = ModifiersFromEvent(event);
 
   result.timeStampSeconds = [event timestamp];
 
+  NSEventSubtype subtype = NSMouseEventSubtype;
+  if ([event type] != NSMouseExited && [event type] != NSMouseEntered)
+    subtype = [event subtype];
+  // For the mouse events and the touchpad events, the pointer type is mouse.
+  // For all tablet events, the pointer type will be just pen.
+  if (subtype == NSTabletPointEventSubtype ||
+      subtype == NSTabletProximityEventSubtype) {
+    result.pointerType = blink::WebPointerProperties::PointerType::Pen;
+    return result;
+  }
+
+  // Set the pointerType based on if the pointing device enters or leaves the
+  // proximity of its tablet.
+  result.pointerType = pointerType;
   return result;
 }
 
 // WebMouseWheelEvent ---------------------------------------------------------
 
 blink::WebMouseWheelEvent WebMouseWheelEventBuilder::Build(
     NSEvent* event,
     NSView* view,
     bool can_rubberband_left,
     bool can_rubberband_right) {
@@ skipping 189 matching lines @@
       break;
     default:
       NOTIMPLEMENTED();
       result.type = blink::WebInputEvent::Undefined;
   }
 
   return result;
 }
 
 }  // namespace content