Fix uaf in ApplicationInstance.

mojo/shell/application_manager.h

Index: mojo/shell/application_manager.h
diff --git a/mojo/shell/application_manager.h b/mojo/shell/application_manager.h
index fa7cbd85a9b93d53fda7f55a9f63382239f73f47..e744a8a856d1727277b864786e2a617767d4ca48 100644
--- a/mojo/shell/application_manager.h
+++ b/mojo/shell/application_manager.h
@@ -153,6 +153,8 @@ class ApplicationManager {
   void OnContentHandlerConnectionClosed(
       ContentHandlerConnection* content_handler);
 
+  ApplicationInstance* GetApplicationInstance(const Identity& identity) const;
+
  private:
   using ApplicationPackagedAlias = std::map<GURL, std::pair<GURL, std::string>>;
   using IdentityToApplicationInstanceMap =
@@ -194,9 +196,6 @@ class ApplicationManager {
       CapabilityFilterPtr filter,
       const base::Closure& on_application_end);
 
-  ApplicationInstance* GetApplicationInstance(const GURL& url,
-                                              const std::string& qualifier);
-
   // Called once |fetcher| has found app. |requested_url| is the url of the
   // requested application before any mappings/resolution have been applied.
   void HandleFetchCallback(ApplicationInstance* originator,