oox: check for namespace in MCE is flawed, use a namespace list

In "AlternateContent" nodes we have to check if we support the
namespace which is provided in "Requires" attribute of "Choice".
Currently we tried to resolve the namespace with a call to the
xml filter, however this doesn't work as the filter is already
gone.
In writerfilter we also have to handle a similar situation but
there we just compare it to a list of predefined namespace alias
("wps" and "wpg").
This commit adds a list of supported namespace aliases to
fragmenthandler2 instead of the namespace checking to support
the "p14" namespace alias correctly.

Change-Id: I25c430b97336c9e140bb5641a76a60895734b91f

oox/source/core/fragmenthandler2.cxx

@@ -60,15 +60,21 @@ bool FragmentHandler2::prepareMceContext( sal_Int32 nElement, const AttributeLis
 
         case MCE_TOKEN( Choice ):
             {
-                OUString aRequires = rAttribs.getString( ( XML_Requires ), "none" );
-                if (!getFilter().hasNamespaceURL(aRequires))
-                    // Check to see if we have this namespace defined first,
-                    // because calling getNamespaceURL() would throw if the
-                    // namespace doesn't exist.
+                if (aMceState.empty() || aMceState.back() != MCE_STARTED)
                     return false;
 
-                aRequires = getFilter().getNamespaceURL( aRequires );
-                if( getFilter().getNamespaceId( aRequires ) > 0 && !aMceState.empty() && aMceState.back() == MCE_STARTED )
+                OUString aRequires = rAttribs.getString( (XML_Requires ), OUString("none") );
+
+                // At this point we can't access namespaces as the correct xml filter
+                // is long gone. For now let's decide depending on a list of supported
+                // namespaces like we do in writerfilter
+
+                static std::vector<OUString> aSupportedNS =
+                {
+                    "p14",
+                };
+
+                if (std::find(aSupportedNS.begin(), aSupportedNS.end(), aRequires) != aSupportedNS.end())
                     aMceState.back() = MCE_FOUND_CHOICE;
                 else
                     return false;