Links in platform apps should open in the system default browser.

chrome/browser/ui/extensions/shell_window.h

Index: chrome/browser/ui/extensions/shell_window.h
diff --git a/chrome/browser/ui/extensions/shell_window.h b/chrome/browser/ui/extensions/shell_window.h
index b0e592b36fa3b656430ad29c50ee9daf58119474..d0971b3a3468e7cfd7b982fbea7daac769ce8b52 100644
--- a/chrome/browser/ui/extensions/shell_window.h
+++ b/chrome/browser/ui/extensions/shell_window.h
@@ -20,6 +20,7 @@ class GURL;
 class Profile;
 class TabContents;
 class NativeShellWindow;
+class ExternalWebContentImpl;
 
 namespace content {
 class WebContents;
@@ -175,6 +176,9 @@ class ShellWindow : public content::NotificationObserver,
   content::NotificationRegistrar registrar_;
   ExtensionFunctionDispatcher extension_function_dispatcher_;
 
+  // Web content delegate for link navigation.
+  scoped_ptr<ExternalWebContentImpl> external_content_delegate_;
+
   scoped_ptr<NativeShellWindow> native_window_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellWindow);