Add back functionality erroneously removed

...with 09d5b31e "loplugin:constantfunction:
store," which apparently over-eagerly reduced functionality that happened to be
constant in one specific implicit instantiation of a template, but not in
others.

(Plus, adapting the original code to silence false loplugin:staticmethods
warnings.)

Change-Id: I156df3aef1b3b0c9d36b2a54c57de29948749bde

store/source/storbase.hxx

@@ -751,7 +751,9 @@ public:
             return store_E_InvalidAccess;
         pHead->guard(nAddr);
 
-        OSL_PRECOND(dynamic_page_cast<T>(pHead) != 0, "store::PageHolder<T>::guard(): Null pointer");
+        T * pImpl = dynamic_page_cast<T>(pHead);
+        OSL_PRECOND(pImpl != 0, "store::PageHolder<T>::guard(): Null pointer");
+        pImpl->guard();
 
         return store_E_None;
     }
@@ -769,7 +771,7 @@ public:
         if (!pImpl)
             return store_E_WrongVersion;
 
-        return store_E_None;
+        return pImpl->verify();
     }
 };
 

store/source/stordata.hxx

@@ -87,6 +87,16 @@ struct OStoreDataPageData : public store::OStorePageData
         if (capacity()) memset (m_pData, 0, capacity());
     }
 
+    /** guard (external representation).
+    */
+    void guard() { (void) this; /* loplugin:staticmethods */ }
+
+    /** verify (external representation).
+    */
+    storeError verify() const {
+        (void) this; // loplugin:staticmethods
+        return store_E_None;
+    }
 };
 
 /*========================================================================