Documents what ApplicationManager::Delegate do

shell/application_manager/application_manager.h

Index: shell/application_manager/application_manager.h
diff --git a/shell/application_manager/application_manager.h b/shell/application_manager/application_manager.h
index 5d1e1c9bd2f8d035a78554904355a1f7ffce2f58..52b9050e9e9d7feebf5c03f3733b513cbd44e47a 100644
--- a/shell/application_manager/application_manager.h
+++ b/shell/application_manager/application_manager.h
@@ -35,9 +35,16 @@ class ApplicationManager {
  public:
   class Delegate {
    public:
-    virtual ~Delegate();
-    virtual GURL ResolveURL(const GURL& url);
-    virtual GURL ResolveMappings(const GURL& url);
+    // Gives the delegate a chance to apply any mappings for the specified url.
+    // This should not resolve 'mojo' urls, that is done by ResolveMojoURL().
+    virtual GURL ResolveMappings(const GURL& url) = 0;
+
+    // Used to map a url with the scheme 'mojo' to the appropriate url. Return
+    // |url| if the scheme is not 'mojo'.
+    virtual GURL ResolveMojoURL(const GURL& url) = 0;
+
+   protected:
+    virtual ~Delegate() {}
   };
 
   // API for testing.