Use smart pointers for graphics device classes

core/fxge/apple/fx_quartz_device.cpp

 // Copyright 2014 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/fxcrt/include/fx_ext.h"
 
 #ifndef _SKIA_SUPPORT_
 #include "core/fxge/agg/fx_agg_driver.h"
@@ skipping 1005 matching lines @@
   if (m_pContext) {
     CGContextRelease(m_pContext);
   }
   m_pContext = context;
   CGContextRetain(m_pContext);
   IFX_RenderDeviceDriver* pDriver =
       new CFX_QuartzDeviceDriver(m_pContext, nDeviceClass);
   SetDeviceDriver(pDriver);
   return TRUE;
 }
+
 FX_BOOL CFX_QuartzDevice::Attach(CFX_DIBitmap* pBitmap) {
   SetBitmap(pBitmap);
   m_pContext = createContextWithBitmap(pBitmap);
   if (!m_pContext)
     return FALSE;
 
   IFX_RenderDeviceDriver* pDriver =
       new CFX_QuartzDeviceDriver(m_pContext, FXDC_DISPLAY);
   SetDeviceDriver(pDriver);
   return TRUE;
 }
+
 FX_BOOL CFX_QuartzDevice::Create(int32_t width,
                                  int32_t height,
                                  FXDIB_Format format) {
   if ((uint8_t)format < 32) {
     return FALSE;
   }
-  CFX_DIBitmap* pBitmap = new CFX_DIBitmap;
-  if (!pBitmap->Create(width, height, format)) {
-    delete pBitmap;
+  std::unique_ptr<CFX_DIBitmap> pBitmap(new CFX_DIBitmap);
+  if (!pBitmap->Create(width, height, format))
     return FALSE;
-  }
   m_bOwnedBitmap = TRUE;
-  return Attach(pBitmap);
+  return Attach(pBitmap.release());
 }
 #endif  // _FXM_PLATFORM_  == _FXM_PLATFORM_APPLE_