updating string example/test to include an example of [shared]

js/src/xpconnect/idl/xpctest.idl

@@ -108,4 +108,5 @@ interface nsIXPCTestNoisy : nsISupports {
 interface nsIXPCTestString : nsISupports {
     string GetStringA();
     void GetStringB(out string s);
+    void GetStringC([shared,retval] out string s);
 };

js/src/xpconnect/tests/components/xpctest_string.cpp

@@ -31,6 +31,9 @@ public:
     /* void GetStringB (out string s); */
     NS_IMETHOD GetStringB(char **s);
 
+    /* void GetStringC ([shared, retval] out string s); */
+    NS_IMETHOD GetStringC(const char **s);
+
     xpcstringtest();
     virtual ~xpcstringtest();
 };
@@ -77,6 +80,18 @@ xpcstringtest::GetStringB(char **s)
     return *s ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
 }
 
+
+/* void GetStringC ([shared, retval] out string s); */
+NS_IMETHODIMP
+xpcstringtest::GetStringC(const char **s)
+{
+    static const char myResult[] = "result of xpcstringtest::GetStringC";
+    if(!s)
+        return NS_ERROR_NULL_POINTER;
+    *s = myResult;
+    return NS_OK;
+}
+
 /***************************************************************************/
 
 // static