[rust png] Remove unused `ProgressiveDecoder::src_pass_number_` field.

After https://pdfium-review.googlesource.com/137272 this field is unused
and can be removed.  As a consequence, the `interlace` parameter can
also be removed from `GetRecordPosition` and
`GifInputRecordPositionBuf`.

Bug: 444045690
Change-Id: I66c2076c2ce794b1a1e9673f18006592cee17ab9
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/137273
Commit-Queue: Łukasz Anforowicz <lukasza@google.com>
Reviewed-by: Lei Zhang <thestig@chromium.org>

core/fxcodec/gif/cfx_gifcontext.cpp

diff --git a/core/fxcodec/gif/cfx_gifcontext.cpp b/core/fxcodec/gif/cfx_gifcontext.cpp
index 373bec0..9a0ae91 100644
--- a/core/fxcodec/gif/cfx_gifcontext.cpp
+++ b/core/fxcodec/gif/cfx_gifcontext.cpp
@@ -43,11 +43,10 @@
                                        int32_t width,
                                        int32_t height,
                                        pdfium::span<CFX_GifPalette> pal,
-                                       int32_t trans_index,
-                                       bool interlace) {
+                                       int32_t trans_index) {
   return delegate_->GifInputRecordPositionBuf(
-      cur_pos, FX_RECT(left, top, left + width, top + height), pal, trans_index,
-      interlace);
+      cur_pos, FX_RECT(left, top, left + width, top + height), pal,
+      trans_index);
 }
 
 GifDecoder::Status CFX_GifContext::ReadHeader() {
@@ -180,8 +179,7 @@
       bool bRes = GetRecordPosition(
           gif_image->data_pos, gif_image->image_info.left,
           gif_image->image_info.top, gif_image->image_info.width,
-          gif_image->image_info.height, pLocalPalette, -1,
-          gif_image->image_info.local_flags.interlace);
+          gif_image->image_info.height, pLocalPalette, -1);
       if (!bRes) {
         gif_image->row_buffer.clear();
         return GifDecoder::Status::kError;
@@ -193,8 +191,7 @@
           gif_image->image_info.height, pLocalPalette,
           gif_image->image_GCE->gce_flags.transparency
               ? static_cast<int32_t>(gif_image->image_GCE->trans_index)
-              : -1,
-          gif_image->image_info.local_flags.interlace);
+              : -1);
       if (!bRes) {
         gif_image->row_buffer.clear();
         return GifDecoder::Status::kError;

core/fxcodec/gif/cfx_gifcontext.h

diff --git a/core/fxcodec/gif/cfx_gifcontext.h b/core/fxcodec/gif/cfx_gifcontext.h
index 114d56d..abefc05 100644
--- a/core/fxcodec/gif/cfx_gifcontext.h
+++ b/core/fxcodec/gif/cfx_gifcontext.h
@@ -34,8 +34,7 @@
                          int32_t width,
                          int32_t height,
                          pdfium::span<CFX_GifPalette> pal,
-                         int32_t trans_index,
-                         bool interlace);
+                         int32_t trans_index);
   GifDecoder::Status ReadHeader();
   GifDecoder::Status GetFrame();
   GifDecoder::Status LoadFrame(size_t frame_num);

core/fxcodec/gif/gif_decoder.h

diff --git a/core/fxcodec/gif/gif_decoder.h b/core/fxcodec/gif/gif_decoder.h
index 3d7a4ca..ef106af 100644
--- a/core/fxcodec/gif/gif_decoder.h
+++ b/core/fxcodec/gif/gif_decoder.h
@@ -35,8 +35,7 @@
     virtual bool GifInputRecordPositionBuf(uint32_t rcd_pos,
                                            const FX_RECT& img_rc,
                                            pdfium::span<CFX_GifPalette> pal_ptr,
-                                           int32_t trans_index,
-                                           bool interlace) = 0;
+                                           int32_t trans_index) = 0;
     virtual void GifReadScanline(int32_t row_num,
                                  pdfium::span<uint8_t> row_buf) = 0;
   };

core/fxcodec/progressive_decoder.cpp

diff --git a/core/fxcodec/progressive_decoder.cpp b/core/fxcodec/progressive_decoder.cpp
index 2672a8e..2abc1eb 100644
--- a/core/fxcodec/progressive_decoder.cpp
+++ b/core/fxcodec/progressive_decoder.cpp
@@ -125,8 +125,7 @@
     uint32_t rcd_pos,
     const FX_RECT& img_rc,
     pdfium::span<CFX_GifPalette> pal_span,
-    int32_t trans_index,
-    bool interlace) {
+    int32_t trans_index) {
   offset_ = rcd_pos;
 
   FXCODEC_STATUS error_status = FXCODEC_STATUS::kError;
@@ -148,7 +147,6 @@
   }
   gif_trans_index_ = trans_index;
   gif_frame_rect_ = img_rc;
-  src_pass_number_ = interlace ? 4 : 1;
   int32_t pal_index = gif_bg_index_;
   RetainPtr<CFX_DIBitmap> pDevice = device_bitmap_;
   if (trans_index >= static_cast<int>(pal_span.size())) {
@@ -797,7 +795,6 @@
   src_height_ = 0;
   src_components_count_ = 0;
   src_bits_per_component_ = 0;
-  src_pass_number_ = 0;
   if (imageType != FXCODEC_IMAGE_UNKNOWN &&
       DetectImageType(imageType, pAttribute)) {
     image_type_ = imageType;

core/fxcodec/progressive_decoder.h

diff --git a/core/fxcodec/progressive_decoder.h b/core/fxcodec/progressive_decoder.h
index 70764bc..01add0b 100644
--- a/core/fxcodec/progressive_decoder.h
+++ b/core/fxcodec/progressive_decoder.h
@@ -98,8 +98,7 @@
   bool GifInputRecordPositionBuf(uint32_t rcd_pos,
                                  const FX_RECT& img_rc,
                                  pdfium::span<CFX_GifPalette> pal_span,
-                                 int32_t trans_index,
-                                 bool interlace) override;
+                                 int32_t trans_index) override;
   void GifReadScanline(int32_t row_num, pdfium::span<uint8_t> row_buf) override;
 #endif  // PDF_ENABLE_XFA_GIF
 
@@ -211,11 +210,6 @@
   TransformMethod trans_method_;
   int src_row_ = 0;
   FXCodec_Format src_format_ = FXCodec_Invalid;
-
-  // TODO(https://crbug.com/444045690): Remove `src_pass_number_` field, because
-  // it is never read from (only written to).
-  int src_pass_number_ = 0;
-
   size_t frame_number_ = 0;
   size_t frame_cur_ = 0;
 #ifdef PDF_ENABLE_XFA_GIF