Pass matrix to CPDF_ClipPath::Transform() by const-ref.

It's never null - either &var or the caller is checking for nullness first.

Change-Id: I84ab44275095eda3023810312b27d84d85fb0293
Reviewed-on: https://pdfium-review.googlesource.com/c/47513
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fxge/cfx_pathdata.h b/core/fxge/cfx_pathdata.h
index 9d96407..705447c 100644
--- a/core/fxge/cfx_pathdata.h
+++ b/core/fxge/cfx_pathdata.h
@@ -49,7 +49,7 @@
   CFX_FloatRect GetBoundingBox() const;
   CFX_FloatRect GetBoundingBox(float line_width, float miter_limit) const;
 
-  void Transform(const CFX_Matrix* pMatrix);
+  void Transform(const CFX_Matrix& matrix);
   bool IsRect() const;
   bool GetZeroAreaPath(const CFX_Matrix* pMatrix,
                        bool bAdjust,