Add tooltip text for chrome shortcut

ash/launcher/launcher_delegate.h

Index: ash/launcher/launcher_delegate.h
diff --git a/ash/launcher/launcher_delegate.h b/ash/launcher/launcher_delegate.h
index e93a73538688fd7e0fec2db0da37cd3c061c5253..848fc1a4aac74d93b7f137b80f43d99b9f1e249f 100644
--- a/ash/launcher/launcher_delegate.h
+++ b/ash/launcher/launcher_delegate.h
@@ -25,6 +25,10 @@ class ASH_EXPORT LauncherDelegate {
   // tab.
   virtual void CreateNewTab() = 0;
 
+  // Invoked when the user clicks on button in the launcher to create a new
+  // window.
+  virtual void CreateNewWindow() = 0;
+
   // Invoked when the user clicks on a window entry in the launcher.
   virtual void ItemClicked(const LauncherItem& item) = 0;