SYMBOL_LIBRARY_MANAGER: Clarify UpdateBuffer ownership

Again, this doesn't retain part-ownership of the pointer
and null is a wxCHECK failure. So hoist the null check
and then handle it as a ref (=non null, caller owns).

Also fixes a trivial mem leak in test_symbol_library_manager.cpp.

eeschema/symbol_library_manager.cpp

@@ -507,9 +507,9 @@ bool SYMBOL_LIBRARY_MANAGER::UpdateSymbolAfterRename( LIB_SYMBOL* aSymbol, const
     LIB_BUFFER&                    libBuf = getLibraryBuffer( aLibrary );
     std::shared_ptr<SYMBOL_BUFFER> symbolBuf = libBuf.GetBuffer( aOldName );
 
-    wxCHECK( symbolBuf, false );
+    wxCHECK( symbolBuf && aSymbol, false );
 
-    libBuf.UpdateBuffer( symbolBuf, aSymbol );
+    libBuf.UpdateBuffer( *symbolBuf, *aSymbol );
     OnDataChanged();
 
     return true;
@@ -949,15 +949,13 @@ bool LIB_BUFFER::CreateBuffer( LIB_SYMBOL* aCopy, SCH_SCREEN* aScreen )
 }
 
 
-bool LIB_BUFFER::UpdateBuffer( std::shared_ptr<SYMBOL_BUFFER> aSymbolBuf, LIB_SYMBOL* aCopy )
+bool LIB_BUFFER::UpdateBuffer( SYMBOL_BUFFER& aSymbolBuf, const LIB_SYMBOL& aCopy )
 {
-    wxCHECK( aCopy && aSymbolBuf, false );
-
-    LIB_SYMBOL* bufferedSymbol = aSymbolBuf->GetSymbol();
+    LIB_SYMBOL* bufferedSymbol = aSymbolBuf.GetSymbol();
 
     wxCHECK( bufferedSymbol, false );
 
-    *bufferedSymbol = *aCopy;
+    *bufferedSymbol = aCopy;
     ++m_hash;
 
     return true;

eeschema/symbol_library_manager.h

@@ -108,7 +108,7 @@ public:
     bool CreateBuffer( LIB_SYMBOL* aCopy, SCH_SCREEN* aScreen );
 
     ///< Update the buffered symbol with the contents of \a aCopy.
-    bool UpdateBuffer( std::shared_ptr<SYMBOL_BUFFER> aSymbolBuf, LIB_SYMBOL* aCopy );
+    bool UpdateBuffer( SYMBOL_BUFFER& aSymbolBuf, const LIB_SYMBOL& aCopy );
 
     /**
      * Delete the given symbol buffer from the library buffer.

qa/tests/eeschema/test_symbol_library_manager.cpp

@@ -127,11 +127,13 @@ BOOST_AUTO_TEST_CASE( LibBuffer )
     BOOST_CHECK_EQUAL( symbolNames[0], childSymbol1->GetName() );
 
     std::shared_ptr<SYMBOL_BUFFER> buf = libBuffer.GetBuffer( parentSymbol1->GetName() );
-    LIB_SYMBOL* tmp = new LIB_SYMBOL( *parentSymbol1 );
-    tmp->GetDescriptionField().SetText( wxS( "Description" ) );
-    libBuffer.UpdateBuffer( buf, tmp );
+
+    LIB_SYMBOL tmp( *parentSymbol1 );
+    tmp.GetDescriptionField().SetText( wxS( "Description" ) );
+
+    libBuffer.UpdateBuffer( *buf, tmp );
     BOOST_CHECK_EQUAL( libBuffer.GetHash(), 4 );
-    BOOST_CHECK( *libBuffer.GetSymbol( parentSymbol1->GetName() ) == *tmp );
+    BOOST_CHECK( *libBuffer.GetSymbol( parentSymbol1->GetName() ) == tmp );
 
     const bool deletedOk = libBuffer.DeleteBuffer( *buf );
     BOOST_CHECK( deletedOk );