Send pointerleave and pointerenter events for styluses 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 45c37416b0d02e754e0700ceaed613b8fbff8bc2..b5b4c4c54f7ba4245f91b2bd2f34155552be8513 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
@@ -327,7 +327,10 @@ blink::WebKeyboardEvent WebKeyboardEventBuilder::Build(NSEvent* event) {
 
 // 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;
@@ -394,11 +397,11 @@ blink::WebMouseEvent WebMouseEventBuilder::Build(NSEvent* event, NSView* view) {
 
   result.timeStampSeconds = [event timestamp];
 
-  // For NSMouseExited and NSMouseEntered, they do not have a subtype. Styluses
-  // and mouses share the same cursor, so we will set their pointerType as
-  // Unknown for now.
+  // For NSMouseExited and NSMouseEntered events, they do not have a subtype.
+  // We decide their pointer types by checking if we recevied a

[mustaq, 2016/10/14 16:07:16]

Please clarify that the check is done at the caller: "...by checking (at the
caller) if..."

+  // NSTabletProximity event.
   if (type == NSMouseExited || type == NSMouseEntered) {
-    result.pointerType = blink::WebPointerProperties::PointerType::Unknown;
+    result.pointerType = pointerType;
     return result;
   }
 
@@ -420,6 +423,10 @@ blink::WebMouseEvent WebMouseEventBuilder::Build(NSEvent* event, NSView* view) {
     NSPoint tilt = [event tilt];
     result.tiltX = lround(tilt.x * 90);
     result.tiltY = lround(tilt.y * 90);
+  } else {
+    result.type = [event isEnteringProximity]
+                      ? blink::WebInputEvent::MouseMove
+                      : blink::WebInputEvent::MouseLeave;
   }
   return result;
 }