Implement notifications for the DisplayBalloon method on Linux and Mac.

chrome/browser/ui/cocoa/status_icons/status_icon_mac.mm

Index: chrome/browser/ui/cocoa/status_icons/status_icon_mac.mm
diff --git a/chrome/browser/ui/cocoa/status_icons/status_icon_mac.mm b/chrome/browser/ui/cocoa/status_icons/status_icon_mac.mm
index 81042985850eed5f9f01d3ae49a82bc907c18d27..317541f9ab13dcf7c104823a5ca02ec2d9160d78 100644
--- a/chrome/browser/ui/cocoa/status_icons/status_icon_mac.mm
+++ b/chrome/browser/ui/cocoa/status_icons/status_icon_mac.mm
@@ -76,14 +76,6 @@ void StatusIconMac::SetToolTip(const string16& tool_tip) {
   [item() setToolTip:base::SysUTF16ToNSString(tool_tip)];
 }
 
-void StatusIconMac::DisplayBalloon(const SkBitmap& icon,
-                                   const string16& title,
-                                   const string16& contents) {
-  // TODO(atwilson): Figure out the right UI to display here when actually
-  // needed (not yet called).
-  // http://crbug.com/74970
-}
-
 void StatusIconMac::UpdatePlatformContextMenu(ui::MenuModel* menu) {
   // TODO(atwilson): Add support for context menus for Mac when actually needed
   // (not yet used by anything) - http://crbug.com/37375.