Reuse GetObjectClippedRect() in CPDF_RenderStatus::ProcessShading().

Part of ProcessShading() looks exactly like GetObjectClippedRect().

Change-Id: I2da46a1f21b8a20bc81ee759b729ea10326ed843
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/98531
Reviewed-by: Nigi <nigi@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/core/fpdfapi/render/cpdf_renderstatus.cpp b/core/fpdfapi/render/cpdf_renderstatus.cpp
index e2a63e3..9772b44 100644
--- a/core/fpdfapi/render/cpdf_renderstatus.cpp
+++ b/core/fpdfapi/render/cpdf_renderstatus.cpp
@@ -1177,9 +1177,7 @@
 
 void CPDF_RenderStatus::ProcessShading(const CPDF_ShadingObject* pShadingObj,
                                        const CFX_Matrix& mtObj2Device) {
-  FX_RECT rect = pShadingObj->GetTransformedBBox(mtObj2Device);
-  FX_RECT clip_box = m_pDevice->GetClipBox();
-  rect.Intersect(clip_box);
+  FX_RECT rect = GetObjectClippedRect(pShadingObj, mtObj2Device);
   if (rect.IsEmpty())
     return;