Rename IFWL_App to CFWL_App

This class is not an interface but a concrete implementation. Rename to match.

Review-Url: https://codereview.chromium.org/2521303002
diff --git a/xfa/fwl/core/cfwl_barcode.cpp b/xfa/fwl/core/cfwl_barcode.cpp
index 00bf829..97249c9 100644
--- a/xfa/fwl/core/cfwl_barcode.cpp
+++ b/xfa/fwl/core/cfwl_barcode.cpp
@@ -18,7 +18,7 @@
 
 }  // namespace
 
-CFWL_Barcode::CFWL_Barcode(const IFWL_App* app)
+CFWL_Barcode::CFWL_Barcode(const CFWL_App* app)
     : CFWL_Edit(app), m_dwAttributeMask(FWL_BCDATTRIBUTE_NONE) {}
 
 CFWL_Barcode::~CFWL_Barcode() {}