Remove explicit CFX_Matrix identity matrix instantiations.

Change-Id: I96c3429dbe2c572ed409706adfe3707b8b9bf51b
Reviewed-on: https://pdfium-review.googlesource.com/6176
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/xfa/fwl/cfwl_combobox.cpp b/xfa/fwl/cfwl_combobox.cpp
index ba72d3d..cdb4f81 100644
--- a/xfa/fwl/cfwl_combobox.cpp
+++ b/xfa/fwl/cfwl_combobox.cpp
@@ -618,7 +618,7 @@
 void CFWL_ComboBox::DisForm_DrawWidget(CFX_Graphics* pGraphics,
                                        const CFX_Matrix* pMatrix) {
   IFWL_ThemeProvider* pTheme = m_pProperties->m_pThemeProvider;
-  CFX_Matrix mtOrg(1, 0, 0, 1, 0, 0);
+  CFX_Matrix mtOrg;
   if (pMatrix)
     mtOrg = *pMatrix;