Make stylus's eraser button work on Mac

content/browser/renderer_host/input/web_input_event_builders_mac.mm

Index: content/browser/renderer_host/input/web_input_event_builders_mac.mm
diff --git a/content/browser/renderer_host/input/web_input_event_builders_mac.mm b/content/browser/renderer_host/input/web_input_event_builders_mac.mm
index 383e02c52f432cdd86e9eab44a10b7c83adccc3f..25be0f5655c762a5e3838ebd12455b4bc9380859 100644
--- a/content/browser/renderer_host/input/web_input_event_builders_mac.mm
+++ b/content/browser/renderer_host/input/web_input_event_builders_mac.mm
@@ -321,11 +321,11 @@ blink::WebMouseEvent WebMouseEventBuilder::Build(
   result.button = button;
   SetWebEventLocationFromEventInView(&result, event, view);
 
+  result.pointerType = pointerType;
   // For NSMouseExited and NSMouseEntered events, they do not have a subtype.

[mustaq, 2017/03/13 14:41:38]

This comment and the comment in the next block no longer applies here.

- I think the other file covers these comments now but not sure. Please
double-check.

- Combine the two |if|s below into one: return early if NSMouseExited ||
NSMouseEntered || (not NSTabletPointEventSubtype &&
!NSTabletProximityEventSubtype).

   // We decide their pointer types by checking if we recevied a
   // NSTabletProximity event.
   if (type == NSMouseExited || type == NSMouseEntered) {
-    result.pointerType = pointerType;
     return result;
   }
 
@@ -334,13 +334,11 @@ blink::WebMouseEvent WebMouseEventBuilder::Build(
   NSEventSubtype subtype = [event subtype];
   if (subtype != NSTabletPointEventSubtype &&
       subtype != NSTabletProximityEventSubtype) {
-    result.pointerType = blink::WebPointerProperties::PointerType::Mouse;
     return result;
   }
 
   // Set stylus properties for events with a subtype of
   // NSTabletPointEventSubtype.
-  result.pointerType = blink::WebPointerProperties::PointerType::Pen;
   result.id = [event deviceID];
   if (subtype == NSTabletPointEventSubtype) {
     result.force = [event pressure];