Pass retained image to CPDF_ImageObject::SetImage()

Turns out all callers are already passing rvalues, so no other
modifications needed.

Change-Id: I856e84fdb1bd33f8c38b0e1e227d87b5ea24fd58
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/95770
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

core/fpdfapi/page/cpdf_imageobject.cpp

diff --git a/core/fpdfapi/page/cpdf_imageobject.cpp b/core/fpdfapi/page/cpdf_imageobject.cpp
index 345092c..0633ed1 100644
--- a/core/fpdfapi/page/cpdf_imageobject.cpp
+++ b/core/fpdfapi/page/cpdf_imageobject.cpp
@@ -6,6 +6,8 @@
 
 #include "core/fpdfapi/page/cpdf_imageobject.h"
 
+#include <utility>
+
 #include "core/fpdfapi/page/cpdf_docpagedata.h"
 #include "core/fpdfapi/page/cpdf_image.h"
 #include "core/fpdfapi/parser/cpdf_stream.h"
@@ -50,9 +52,9 @@
   SetRect(m_Matrix.TransformRect(kRect));
 }
 
-void CPDF_ImageObject::SetImage(const RetainPtr<CPDF_Image>& pImage) {
+void CPDF_ImageObject::SetImage(RetainPtr<CPDF_Image> pImage) {
   MaybePurgeCache();
-  m_pImage = pImage;
+  m_pImage = std::move(pImage);
 }
 
 RetainPtr<CPDF_Image> CPDF_ImageObject::GetImage() const {

core/fpdfapi/page/cpdf_imageobject.h

diff --git a/core/fpdfapi/page/cpdf_imageobject.h b/core/fpdfapi/page/cpdf_imageobject.h
index 5e0ee4b..af18da4 100644
--- a/core/fpdfapi/page/cpdf_imageobject.h
+++ b/core/fpdfapi/page/cpdf_imageobject.h
@@ -28,7 +28,7 @@
   const CPDF_ImageObject* AsImage() const override;
 
   void CalcBoundingBox();
-  void SetImage(const RetainPtr<CPDF_Image>& pImage);
+  void SetImage(RetainPtr<CPDF_Image> pImage);
   RetainPtr<CPDF_Image> GetImage() const;
   RetainPtr<CFX_DIBitmap> GetIndependentBitmap() const;