SAL_WARN when using the interal GraphicObject URL

Write a warn if a URL is created from a internal GraphicObject
URL as this is now deprecated.

Extract the way to determine if a URL is internal to its own
function, so it can be used to check and rewrite places that use
it.

Change-Id: Iedf13a596eab839094ea98e41787865bf6783adf
Reviewed-on: https://gerrit.libreoffice.org/47495Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>
Tested-by: Tomaž Vajngerl <quikee@gmail.com>

include/svtools/grfmgr.hxx

@@ -465,7 +465,9 @@ public:
 
     void                    StopAnimation( OutputDevice* pOut = nullptr, long nExtraData = 0 );
 
-    static GraphicObject    CreateGraphicObjectFromURL( const OUString &rURL );
+    static bool isGraphicObjectUniqueIdURL(OUString const & rURL);
+    static GraphicObject CreateGraphicObjectFromURL(OUString const & rURL);
+
     // will inspect an object ( e.g. a control ) for any 'ImageURL'
     // properties and return these in a vector. Note: this implementation
     // will cater for XNameContainer objects and deep inspect any containers

svtools/source/graphic/grfmgr.cxx

@@ -1039,11 +1039,18 @@ IMPL_LINK_NOARG(GraphicObject, ImplAutoSwapOutHdl, Timer *, void)
 
 #define UNO_NAME_GRAPHOBJ_URLPREFIX "vnd.sun.star.GraphicObject:"
 
-GraphicObject GraphicObject::CreateGraphicObjectFromURL( const OUString &rURL )
+bool GraphicObject::isGraphicObjectUniqueIdURL(OUString const & rURL)
 {
-    const OUString aPrefix( UNO_NAME_GRAPHOBJ_URLPREFIX );
-    if( rURL.startsWith( aPrefix ) )
+    const OUString aPrefix(UNO_NAME_GRAPHOBJ_URLPREFIX);
+    return rURL.startsWith(aPrefix);
+}
+
+GraphicObject GraphicObject::CreateGraphicObjectFromURL(OUString const & rURL)
+{
+    if (GraphicObject::isGraphicObjectUniqueIdURL(rURL))
     {
+        SAL_WARN("vcl", "Deprecated URL '" << rURL << "' was used to create a GraphicObject");
+
         // graphic manager url
         OString aUniqueID(OUStringToOString(rURL.copy(sizeof(UNO_NAME_GRAPHOBJ_URLPREFIX) - 1), RTL_TEXTENCODING_UTF8));
         return GraphicObject( aUniqueID );