[OSX] Add iconsAreTemplates property to Tray API objects

Add boolean property (defaults to `true`) `iconsAreTemplates` to `Tray` objects
to allow for proper display of icons in Mac OS X (Yosemite) Dark Menus.

When `iconsAreTemplates` is set to true, both `icon` and `altIcon` are treated
as "templates" and the system automatically ensures proper styling according to
the various states of the status item (e.g. dark menu, light menu, etc.).
Template images should consist only of black and clear colours and can use the
alpha channel in the image to adjust the opacity of black content.

See [Dark Menus in AppKit Release Notes for OS X v10.10](https://developer.apple.com/library/mac/releasenotes/AppKit/RN-AppKit/#10_10DarkMenus)
and [`NSImage setTemplate:`](https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ApplicationKit/Classes/NSImage_Class/index.html#//apple_ref/occ/instm/NSImage/setTemplate:).

On Linux and Windows setting the property has no effect.

FIX nwjs#2476

src/api/tray/tray.cc

@@ -37,6 +37,10 @@ Tray::Tray(int id,
   if (option.GetString("title", &title))
     SetTitle(title);
 
+  bool areTemplates;
+  if (option.GetBoolean("iconsAreTemplates", &areTemplates))
+    SetIconsAreTemplates(areTemplates);
+
   std::string icon;
   if (option.GetString("icon", &icon) && !icon.empty())
     SetIcon(icon);
@@ -74,6 +78,10 @@ void Tray::Call(const std::string& method,
     std::string alticon;
     arguments.GetString(0, &alticon);
     SetAltIcon(alticon);
+  } else if (method == "SetIconsAreTemplates") {
+    bool areTemplates;
+    arguments.GetBoolean(0, &areTemplates);
+    SetIconsAreTemplates(areTemplates);
   } else if (method == "SetTooltip") {
     std::string tooltip;
     arguments.GetString(0, &tooltip);

src/api/tray/tray.h

@@ -69,10 +69,13 @@ class Tray : public Base {
   void Remove();
   // Alternate icons only work with Macs
   void SetAltIcon(const std::string& alticon_path);
+  // Template icons only work with Macs 
+  void SetIconsAreTemplates(bool areTemplates);
 
 #if defined(OS_MACOSX)
   __block NSStatusItem* status_item_;
   MacTrayObserver* status_observer_;
+  bool iconsAreTemplates; 
 #elif 0
   GtkStatusIcon* status_item_;
 

src/api/tray/tray.js

@@ -42,6 +42,11 @@ function Tray(option) {
     option.alticon = nw.getAbsolutePath(option.alticon);
   }
 
+  if (option.hasOwnProperty('iconsAreTemplates'))
+    option.iconsAreTemplates = Boolean(option.iconsAreTemplates);
+  else
+    option.iconsAreTemplates = true;
+
   if (option.hasOwnProperty('tooltip'))
     option.tooltip = String(option.tooltip);
 
@@ -103,6 +108,14 @@ Tray.prototype.__defineSetter__('alticon', function(val) {
   this.handleSetter('alticon', 'SetAlticon', String, real_path);
 });
 
+Tray.prototype.__defineGetter__('iconsAreTemplates', function() {
+  return this.handleGetter('iconsAreTemplates');
+});
+
+Tray.prototype.__defineSetter__('iconsAreTemplates', function(val) {
+  this.handleSetter('iconsAreTemplates', 'SetIconsAreTemplates', Boolean, val);
+});
+
 Tray.prototype.__defineGetter__('tooltip', function() {
   return this.handleGetter('tooltip');
 });

src/api/tray/tray_aura.cc

@@ -107,4 +107,7 @@ void Tray::Remove() {
 void Tray::SetAltIcon(const std::string& alticon_path) {
 }
 
+void Tray::SetIconsAreTemplates(bool areTemplates) {
+}
+
 }  // namespace nwapi

src/api/tray/tray_gtk.cc

@@ -83,4 +83,7 @@ void Tray::OnPopupMenu(GtkWidget* widget, guint button, guint time) {
 void Tray::SetAltIcon(const std::string& alticon_path) {
 }
 
+void Tray::SetIconsAreTemplates(bool areTemplates) {
+}
+
 }  // namespace nwapi

src/api/tray/tray_mac.mm

@@ -72,6 +72,7 @@ - (void)onClick:(id)sender {
   if (!icon.empty()) {
     NSImage* image = [[NSImage alloc]
          initWithContentsOfFile:[NSString stringWithUTF8String:icon.c_str()]];
+    [image setTemplate:iconsAreTemplates];
     [status_item_ setImage:image];
     [image release];
   } else {
@@ -83,13 +84,24 @@ - (void)onClick:(id)sender {
   if (!alticon.empty()) {
     NSImage* image = [[NSImage alloc]
          initWithContentsOfFile:[NSString stringWithUTF8String:alticon.c_str()]];
+    [image setTemplate:iconsAreTemplates];
     [status_item_ setAlternateImage:image];
     [image release];
   } else {
     [status_item_ setAlternateImage:nil];
   }
 }
 
+void Tray::SetIconsAreTemplates(bool areTemplates) {
+  iconsAreTemplates = areTemplates;
+  if ([status_item_ image] != nil) {
+    [[status_item_ image] setTemplate:areTemplates];
+  }
+  if ([status_item_ alternateImage] != nil) {
+    [[status_item_ alternateImage] setTemplate:areTemplates];
+  }
+}
+
 void Tray::SetTooltip(const std::string& tooltip) {
   [status_item_ setToolTip:[NSString stringWithUTF8String:tooltip.c_str()]];
 }