Remove some usage of |return XXX.release()| anti-pattern.

core/fpdfapi/page/cpdf_image.cpp

 // Copyright 2016 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/fpdfapi/page/cpdf_image.h"
 
 #include <algorithm>
 #include <memory>
@@ skipping 304 matching lines @@
   m_bIsMask = pBitmap->IsAlphaMask();
   m_Width = BitmapWidth;
   m_Height = BitmapHeight;
   FX_Free(dest_buf);
 }
 
 void CPDF_Image::ResetCache(CPDF_Page* pPage, const CFX_DIBitmap* pBitmap) {
   pPage->GetRenderCache()->ResetBitmap(m_pStream.Get(), pBitmap);
 }
 
-CFX_DIBSource* CPDF_Image::LoadDIBSource(CFX_DIBSource** ppMask,
-                                         uint32_t* pMatteColor,
-                                         bool bStdCS,
-                                         uint32_t GroupFamily,
-                                         bool bLoadMask) const {
+std::unique_ptr<CFX_DIBSource> CPDF_Image::LoadDIBSource(CFX_DIBSource** ppMask,
+                                                         uint32_t* pMatteColor,
+                                                         bool bStdCS,
+                                                         uint32_t GroupFamily,
+                                                         bool bLoadMask) const {
   auto source = pdfium::MakeUnique<CPDF_DIBSource>();
-  if (source->Load(m_pDocument, m_pStream.Get(),
-                   reinterpret_cast<CPDF_DIBSource**>(ppMask), pMatteColor,
-                   nullptr, nullptr, bStdCS, GroupFamily, bLoadMask)) {
-    return source.release();
+  if (!source->Load(m_pDocument, m_pStream.Get(),
+                    reinterpret_cast<CPDF_DIBSource**>(ppMask), pMatteColor,
+                    nullptr, nullptr, bStdCS, GroupFamily, bLoadMask)) {
+    return nullptr;
   }
-  return nullptr;
+  return std::move(source);
 }
 
 CFX_DIBSource* CPDF_Image::DetachBitmap() {
   CFX_DIBSource* pBitmap = m_pDIBSource;
   m_pDIBSource = nullptr;
   return pBitmap;
 }
 
 CFX_DIBSource* CPDF_Image::DetachMask() {
   CFX_DIBSource* pBitmap = m_pMask;
@@ skipping 32 matching lines @@
   }
   if (!ret) {
     delete m_pDIBSource;
     m_pDIBSource = nullptr;
     return false;
   }
   m_pMask = pSource->DetachMask();
   m_MatteColor = pSource->GetMatteColor();
   return false;
 }