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

content/browser/renderer_host/render_widget_host_view_mac.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 #include <IOSurface/IOSurface.h>
 #include <stddef.h>
@@ skipping 165 matching lines @@
   BOOL suppressNextEscapeKeyUp_;
 
   // The set of key codes from key down events that we haven't seen the matching
   // key up events yet.
   // Used for filtering out non-matching NSKeyUp events.
   std::set<unsigned short> keyDownCodes_;
 
   // The filter used to guide touch events towards a horizontal or vertical
   // orientation.
   content::MouseWheelRailsFilterMac mouseWheelFilter_;
+
+  // This is used to indicate if the pointing device enters or leaves the
+  // proximity of its tablet.
+  BOOL stylusEnteringProximity_;

[tdresser, 2016/05/31 13:05:34]

Should this be stylusWithinProximity?

With this patch, if a hold a stylus near the screen, and move my mouse around,
we'll think it's a stylus, correct?

We should avoid that if possible.

[lanwei, 2016/05/31 14:33:35]

You are right, I should add some checks to the mouse events.

 }
 
 @property(nonatomic, readonly) NSRange selectedRange;
 @property(nonatomic, readonly) BOOL suppressNextEscapeKeyUp;
 
 - (void)setCanBeKeyView:(BOOL)can;
 - (void)setCloseOnDeactivate:(BOOL)b;
 - (void)setOpaque:(BOOL)opaque;
 // True for always-on-top special windows (e.g. Balloons and Panels).
 - (BOOL)acceptsMouseEventsWhenInactive;
@@ skipping 424 matching lines @@
 
   // Factory used to safely scope delayed calls to ShutdownHost().
   base::WeakPtrFactory<RenderWidgetHostViewMac> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewMac);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_