diff --git a/core/fxge/dib/cfx_dibbase.cpp b/core/fxge/dib/cfx_dibbase.cpp
index e5a677c..ddf4df8 100644
--- a/core/fxge/dib/cfx_dibbase.cpp
+++ b/core/fxge/dib/cfx_dibbase.cpp
@@ -1044,3 +1044,7 @@
 #endif
   }
 }
+
+bool CFX_DIBBase::IsPremultiplied() const {
+  return false;
+}
diff --git a/core/fxge/dib/cfx_dibbase.h b/core/fxge/dib/cfx_dibbase.h
index aecc9db..6e70dd5 100644
--- a/core/fxge/dib/cfx_dibbase.h
+++ b/core/fxge/dib/cfx_dibbase.h
@@ -107,15 +107,15 @@
                       int& src_top,
                       const CFX_ClipRgn* pClipRgn) const;
 
+  // Whether alpha is premultiplied (if `IsAlphaFormat()`).
+  virtual bool IsPremultiplied() const;
+
 #if defined(PDF_USE_SKIA)
   // Realizes an `SkImage` from this DIB.
   //
   // This may share the underlying pixels, in which case, this DIB should not be
   // modified during the lifetime of the `SkImage`.
   virtual sk_sp<SkImage> RealizeSkImage() const;
-
-  // Whether alpha is premultiplied (if `IsAlphaFormat()`).
-  virtual bool IsPremultiplied() const;
 #endif  // defined(PDF_USE_SKIA)
 
  protected:
diff --git a/core/fxge/skia/cfx_dibbase_skia.cpp b/core/fxge/skia/cfx_dibbase_skia.cpp
index eda97a1..7d122c2 100644
--- a/core/fxge/skia/cfx_dibbase_skia.cpp
+++ b/core/fxge/skia/cfx_dibbase_skia.cpp
@@ -266,7 +266,3 @@
       NOTREACHED_NORETURN();
   }
 }
-
-bool CFX_DIBBase::IsPremultiplied() const {
-  return false;
-}
diff --git a/fpdfsdk/fpdf_editimg.cpp b/fpdfsdk/fpdf_editimg.cpp
index f0d93eb..f29bc4a 100644
--- a/fpdfsdk/fpdf_editimg.cpp
+++ b/fpdfsdk/fpdf_editimg.cpp
@@ -176,6 +176,7 @@
   if (!holder) {
     return false;
   }
+  CHECK(!holder->IsPremultiplied());
 
   if (pages) {
     for (int index = 0; index < count; index++) {
@@ -272,10 +273,14 @@
       pBitmap = pSource->ConvertTo(FXDIB_Format::kRgb);
       break;
   }
-  if (pBitmap) {
-    CHECK(!pBitmap->HasPalette());
+  if (!pBitmap) {
+    return nullptr;
   }
 
+  CHECK(!pBitmap->HasPalette());
+  CHECK(!pBitmap->IsPremultiplied());
+
+  // Caller takes ownership.
   return FPDFBitmapFromCFXDIBitmap(pBitmap.Leak());
 }
 
diff --git a/fpdfsdk/fpdf_edittext.cpp b/fpdfsdk/fpdf_edittext.cpp
index 4c6ce82..355d3aa 100644
--- a/fpdfsdk/fpdf_edittext.cpp
+++ b/fpdfsdk/fpdf_edittext.cpp
@@ -758,6 +758,8 @@
   if (rect.IsEmpty())
     return nullptr;
 
+  // TODO(crbug.com/42271020): Consider adding support for
+  // `FXDIB_Format::kArgbPremul`
   auto result_bitmap = pdfium::MakeRetain<CFX_DIBitmap>();
   if (!result_bitmap->Create(rect.Width(), rect.Height(), FXDIB_Format::kArgb))
     return nullptr;
@@ -789,6 +791,8 @@
   render_matrix *= scale_matrix;
   status.RenderSingleObject(text, render_matrix);
 
+  CHECK(!result_bitmap->IsPremultiplied());
+
   // Caller takes ownership.
   return FPDFBitmapFromCFXDIBitmap(result_bitmap.Leak());
 }
diff --git a/fpdfsdk/fpdf_formfill.cpp b/fpdfsdk/fpdf_formfill.cpp
index 9b8ee18..19a79ba 100644
--- a/fpdfsdk/fpdf_formfill.cpp
+++ b/fpdfsdk/fpdf_formfill.cpp
@@ -211,6 +211,7 @@
   if (dest_is_bitmap) {
     holder.Reset(absl::get<CFX_DIBitmap*>(dest));
     CHECK(holder);
+    CHECK(!holder->IsPremultiplied());
   } else {
 #if defined(PDF_USE_SKIA)
     if (!CFX_DefaultRenderDevice::UseSkiaRenderer()) {
diff --git a/fpdfsdk/fpdf_progressive.cpp b/fpdfsdk/fpdf_progressive.cpp
index 9c446c5..455d42d 100644
--- a/fpdfsdk/fpdf_progressive.cpp
+++ b/fpdfsdk/fpdf_progressive.cpp
@@ -62,6 +62,7 @@
   if (!pBitmap) {
     return FPDF_RENDER_FAILED;
   }
+  CHECK(!pBitmap->IsPremultiplied());
 
   auto owned_context = std::make_unique<CPDF_PageRenderContext>();
   CPDF_PageRenderContext* context = owned_context.get();
diff --git a/fpdfsdk/fpdf_thumbnail.cpp b/fpdfsdk/fpdf_thumbnail.cpp
index 2bd886d..5e8f211 100644
--- a/fpdfsdk/fpdf_thumbnail.cpp
+++ b/fpdfsdk/fpdf_thumbnail.cpp
@@ -86,5 +86,6 @@
     return nullptr;
   }
 
+  CHECK(!thumb_bitmap->IsPremultiplied());
   return FPDFBitmapFromCFXDIBitmap(thumb_bitmap.Leak());
 }
diff --git a/fpdfsdk/fpdf_view.cpp b/fpdfsdk/fpdf_view.cpp
index 4943746..2c9c79c 100644
--- a/fpdfsdk/fpdf_view.cpp
+++ b/fpdfsdk/fpdf_view.cpp
@@ -712,6 +712,7 @@
   if (!pBitmap) {
     return;
   }
+  CHECK(!pBitmap->IsPremultiplied());
 
   auto owned_context = std::make_unique<CPDF_PageRenderContext>();
   CPDF_PageRenderContext* context = owned_context.get();
@@ -749,6 +750,7 @@
   if (!pBitmap) {
     return;
   }
+  CHECK(!pBitmap->IsPremultiplied());
 
   auto owned_context = std::make_unique<CPDF_PageRenderContext>();
   CPDF_PageRenderContext* context = owned_context.get();
@@ -889,6 +891,10 @@
                        alpha ? FXDIB_Format::kArgb : FXDIB_Format::kRgb32)) {
     return nullptr;
   }
+
+  CHECK(!pBitmap->IsPremultiplied());
+
+  // Caller takes ownership.
   return FPDFBitmapFromCFXDIBitmap(pBitmap.Leak());
 }
 
@@ -918,9 +924,13 @@
   // Ensure external memory is good at least for the duration of this call.
   UnownedPtr<uint8_t> pChecker(static_cast<uint8_t*>(first_scan));
   auto pBitmap = pdfium::MakeRetain<CFX_DIBitmap>();
-  if (!pBitmap->Create(width, height, fx_format, pChecker, stride))
+  if (!pBitmap->Create(width, height, fx_format, pChecker, stride)) {
     return nullptr;
+  }
 
+  CHECK(!pBitmap->IsPremultiplied());
+
+  // Caller takes ownership.
   return FPDFBitmapFromCFXDIBitmap(pBitmap.Leak());
 }
 
@@ -955,6 +965,7 @@
   if (!pBitmap) {
     return;
   }
+  CHECK(!pBitmap->IsPremultiplied());
 
   CFX_DefaultRenderDevice device;
   device.Attach(pBitmap);