add mouse-enter and mouse-exit events for tray

atom/browser/ui/tray_icon.cc

@@ -79,6 +79,16 @@ void TrayIcon::NotifyDropText(const std::string& text) {
     observer.OnDropText(text);
 }
 
+void TrayIcon::NotifyMouseEntered() {
+  for (TrayIconObserver& observer : observers_)
+    observer.OnMouseEntered();
+}
+
+void TrayIcon::NotifyMouseExited() {
+  for (TrayIconObserver& observer : observers_)
+    observer.OnMouseExited();
+}
+
 void TrayIcon::NotifyDragEntered() {
   for (TrayIconObserver& observer : observers_)
     observer.OnDragEntered();

atom/browser/ui/tray_icon.h

@@ -83,6 +83,8 @@ class TrayIcon {
   void NotifyDragEntered();
   void NotifyDragExited();
   void NotifyDragEnded();
+  void NotifyMouseEntered();
+  void NotifyMouseExited();
 
  protected:
   TrayIcon();

atom/browser/ui/tray_icon_cocoa.mm

@@ -54,9 +54,16 @@ const CGFloat kVerticalTitleMargin = 2;
                             statusItemWithLength:NSVariableStatusItemLength];
     statusItem_.reset([item retain]);
     [statusItem_ setView:self];
-
     // Finalize setup by sizing our views
     [self updateDimensions];
+
+    // Add NSTrackingArea for listening to mouseEnter and mouseExit events
+    int opts = (NSTrackingMouseEnteredAndExited | NSTrackingActiveAlways);
+    NSTrackingArea* trackingArea = [[NSTrackingArea alloc] initWithRect:[self bounds]
+                                               options:opts
+                                                 owner:self
+                                              userInfo:nil];
+    [self addTrackingArea:trackingArea];
   }
   return self;
 }
@@ -288,6 +295,14 @@ const CGFloat kVerticalTitleMargin = 2;
   return NSDragOperationCopy;
 }
 
+- (void)mouseExited:(NSEvent*)event {
+    trayIcon_->NotifyMouseExited();
+}
+
+- (void)mouseEntered:(NSEvent*)event {
+    trayIcon_->NotifyMouseEntered();
+}
+
 - (void)draggingExited:(id <NSDraggingInfo>)sender {
   trayIcon_->NotifyDragExited();
 }

atom/browser/ui/tray_icon_observer.h

@@ -28,6 +28,8 @@ class TrayIconObserver {
   virtual void OnDragEntered() {}
   virtual void OnDragExited() {}
   virtual void OnDragEnded() {}
+  virtual void OnMouseEntered() {}
+  virtual void OnMouseExited() {}
 
  protected:
   virtual ~TrayIconObserver() {}