enable skia gradients, fix bugs

core/fxge/skia/fx_skia_device.cpp

Index: core/fxge/skia/fx_skia_device.cpp
diff --git a/core/fxge/skia/fx_skia_device.cpp b/core/fxge/skia/fx_skia_device.cpp
index 84db838807ee53fe77f3b4cf03e1c3152950b536..6b381dffa77cb01b37049036ac4c0fc23f41303a 100644
--- a/core/fxge/skia/fx_skia_device.cpp
+++ b/core/fxge/skia/fx_skia_device.cpp
@@ -1752,7 +1752,7 @@ bool CFX_SkiaDeviceDriver::GetDIBits(CFX_DIBitmap* pBitmap, int left, int top) {
   m_pBitmap->UnPreMultiply();
   FX_RECT rect(left, top, left + pBitmap->GetWidth(),
                top + pBitmap->GetHeight());
-  CFX_DIBitmap* pBack = nullptr;
+  std::unique_ptr<CFX_DIBitmap> pBack = nullptr;
   if (m_pOriDevice) {
     pBack = m_pOriDevice->Clone(&rect);
     if (!pBack)
@@ -1771,12 +1771,11 @@ bool CFX_SkiaDeviceDriver::GetDIBits(CFX_DIBitmap* pBitmap, int left, int top) {
   top = std::min(top, 0);
   if (m_bRgbByteOrder) {
     RgbByteOrderTransferBitmap(pBitmap, 0, 0, rect.Width(), rect.Height(),
-                               pBack, left, top);
+                               pBack.get(), left, top);
   } else {
-    bRet = pBitmap->TransferBitmap(0, 0, rect.Width(), rect.Height(), pBack,
-                                   left, top);
+    bRet = pBitmap->TransferBitmap(0, 0, rect.Width(), rect.Height(),
+                                   pBack.get(), left, top);
   }
-  delete pBack;
   return bRet;
 #endif  // _SKIA_SUPPORT_PATHS_
 }