Pass CFX_Matrix by const-ref in various OnDraw() methods.

Change-Id: I6e953206520c024b2fc23b9b60c5c43112d04896
Reviewed-on: https://pdfium-review.googlesource.com/c/43603
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/fpdfsdk/cpdfsdk_annothandlermgr.cpp b/fpdfsdk/cpdfsdk_annothandlermgr.cpp
index 2fd7f92..3dc3f09 100644
--- a/fpdfsdk/cpdfsdk_annothandlermgr.cpp
+++ b/fpdfsdk/cpdfsdk_annothandlermgr.cpp
@@ -118,10 +118,10 @@
 void CPDFSDK_AnnotHandlerMgr::Annot_OnDraw(CPDFSDK_PageView* pPageView,
                                            CPDFSDK_Annot* pAnnot,
                                            CFX_RenderDevice* pDevice,
-                                           CFX_Matrix* pUser2Device,
+                                           const CFX_Matrix& mtUser2Device,
                                            bool bDrawAnnots) {
   ASSERT(pAnnot);
-  GetAnnotHandler(pAnnot)->OnDraw(pPageView, pAnnot, pDevice, pUser2Device,
+  GetAnnotHandler(pAnnot)->OnDraw(pPageView, pAnnot, pDevice, mtUser2Device,
                                   bDrawAnnots);
 }