Add CFX_DIBSource::GetWritableScanline().

Remove a bunch of const_cast<uint8_t*> or equivalent.  This will also
help when we convert to span<>, since casting spans is a nuisance.

Change-Id: I330e5041cbaf33a84425fc4242a3dfacf5ca8011
Reviewed-on: https://pdfium-review.googlesource.com/39831
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/core/fxge/dib/cfx_bitmapstorer.cpp b/core/fxge/dib/cfx_bitmapstorer.cpp
index f649e0caea..d5b26f28b7 100644
--- a/core/fxge/dib/cfx_bitmapstorer.cpp
+++ b/core/fxge/dib/cfx_bitmapstorer.cpp
@@ -25,10 +25,10 @@ void CFX_BitmapStorer::Replace(RetainPtr<CFX_DIBitmap>&& pBitmap) {
 void CFX_BitmapStorer::ComposeScanline(int line,
                                        const uint8_t* scanline,
                                        const uint8_t* scan_extra_alpha) {
-  uint8_t* dest_buf = const_cast<uint8_t*>(m_pBitmap->GetScanline(line));
+  uint8_t* dest_buf = m_pBitmap->GetWritableScanline(line);
   uint8_t* dest_alpha_buf =
       m_pBitmap->m_pAlphaMask
-          ? const_cast<uint8_t*>(m_pBitmap->m_pAlphaMask->GetScanline(line))
+          ? m_pBitmap->m_pAlphaMask->GetWritableScanline(line)
           : nullptr;
   if (dest_buf)
     memcpy(dest_buf, scanline, m_pBitmap->GetPitch());