diff --git a/image/Deinterlacer.cpp b/image/Deinterlacer.cpp
new file mode 100644
index 000000000000..96a6512c3aa3
--- /dev/null
+++ b/image/Deinterlacer.cpp
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+#include "Downscaler.h"
+
+namespace mozilla {
+namespace image {
+
+Deinterlacer::Deinterlacer(const nsIntSize& aImageSize)
+  : mImageSize(aImageSize)
+  , mBuffer(MakeUnique<uint8_t[]>(mImageSize.width *
+                                  mImageSize.height *
+                                  sizeof(uint32_t)))
+{ }
+
+uint32_t
+Deinterlacer::RowSize() const
+{
+  return mImageSize.width * sizeof(uint32_t);
+}
+
+uint8_t*
+Deinterlacer::RowBuffer(uint32_t aRow)
+{
+  uint32_t offset = aRow * RowSize();
+  MOZ_ASSERT(offset < mImageSize.width * mImageSize.height * sizeof(uint32_t),
+             "Row is outside of image");
+  return mBuffer.get() + offset;
+}
+
+void
+Deinterlacer::PropagatePassToDownscaler(Downscaler& aDownscaler)
+{
+  for (int32_t row = 0 ; row < mImageSize.height ; ++row) {
+    memcpy(aDownscaler.RowBuffer(), RowBuffer(row), RowSize());
+    aDownscaler.CommitRow();
+  }
+}
+
+} // namespace image
+} // namespace mozilla
diff --git a/image/Deinterlacer.h b/image/Deinterlacer.h
new file mode 100644
index 000000000000..74ffd86ea4d1
--- /dev/null
+++ b/image/Deinterlacer.h
@@ -0,0 +1,50 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+/**
+ * Deinterlacer is a utility class to allow Downscaler to work with interlaced
+ * images.
+
+ * Since Downscaler needs to receive rows in top-to-bottom or
+ * bottom-to-top order, it can't natively handle interlaced images, in which the
+ * rows arrive in an interleaved order. Deinterlacer solves this problem by
+ * acting as an intermediate buffer that records decoded rows. Unlike
+ * Downscaler, it allows the rows to be written in arbitrary order. After each
+ * pass, calling PropagatePassToDownscaler() will downscale every buffered row
+ * in a single operation. The rows remain in the buffer, so rows that were
+ * written in one pass will be included in subsequent passes.
+ */
+
+
+#ifndef mozilla_image_Deinterlacer_h
+#define mozilla_image_Deinterlacer_h
+
+#include "Downscaler.h"
+
+namespace mozilla {
+namespace image {
+
+class Deinterlacer
+{
+public:
+  explicit Deinterlacer(const nsIntSize& aImageSize);
+
+  uint8_t* RowBuffer(uint32_t aRow);
+  void PropagatePassToDownscaler(Downscaler& aDownscaler);
+
+private:
+  uint32_t RowSize() const;
+
+  nsIntSize mImageSize;
+  UniquePtr<uint8_t[]> mBuffer;
+};
+
+
+} // namespace image
+} // namespace mozilla
+
+#endif // mozilla_image_Deinterlacer_h
diff --git a/image/Downscaler.cpp b/image/Downscaler.cpp
index a01b67c3a391..d83141b93e84 100644
--- a/image/Downscaler.cpp
+++ b/image/Downscaler.cpp
@@ -314,36 +314,7 @@ Downscaler::DownscaleInputLine()
   }
 }
 
-Deinterlacer::Deinterlacer(const nsIntSize& aImageSize)
-  : mImageSize(aImageSize)
-  , mBuffer(MakeUnique<uint8_t[]>(mImageSize.width *
-                                  mImageSize.height *
-                                  sizeof(uint32_t)))
-{ }
 
-uint32_t
-Deinterlacer::RowSize() const
-{
-  return mImageSize.width * sizeof(uint32_t);
-}
-
-uint8_t*
-Deinterlacer::RowBuffer(uint32_t aRow)
-{
-  uint32_t offset = aRow * RowSize();
-  MOZ_ASSERT(offset < mImageSize.width * mImageSize.height * sizeof(uint32_t),
-             "Row is outside of image");
-  return mBuffer.get() + offset;
-}
-
-void
-Deinterlacer::PropagatePassToDownscaler(Downscaler& aDownscaler)
-{
-  for (int32_t row = 0 ; row < mImageSize.height ; ++row) {
-    memcpy(aDownscaler.RowBuffer(), RowBuffer(row), RowSize());
-    aDownscaler.CommitRow();
-  }
-}
 
 } // namespace image
 } // namespace mozilla
diff --git a/image/Downscaler.h b/image/Downscaler.h
index 4083e83df96e..a455a222c253 100644
--- a/image/Downscaler.h
+++ b/image/Downscaler.h
@@ -162,7 +162,7 @@ public:
   }
 
   uint8_t* RowBuffer() { return nullptr; }
-  void ClearRow(uint32_t = 0);
+  void ClearRow(uint32_t = 0) { }
   void CommitRow() { }
   bool HasInvalidation() const { return false; }
   DownscalerInvalidRect TakeInvalidRect() { return DownscalerInvalidRect(); }
@@ -171,33 +171,7 @@ public:
 
 #endif // MOZ_ENABLE_SKIA
 
-/**
- * Deinterlacer is a utility class to allow Downscaler to work with interlaced
- * images.
 
- * Since Downscaler needs to receive rows in top-to-bottom or
- * bottom-to-top order, it can't natively handle interlaced images, in which the
- * rows arrive in an interleaved order. Deinterlacer solves this problem by
- * acting as an intermediate buffer that records decoded rows. Unlike
- * Downscaler, it allows the rows to be written in arbitrary order. After each
- * pass, calling PropagatePassToDownscaler() will downscale every buffered row
- * in a single operation. The rows remain in the buffer, so rows that were
- * written in one pass will be included in subsequent passes.
- */
-class Deinterlacer
-{
-public:
-  explicit Deinterlacer(const nsIntSize& aImageSize);
-
-  uint8_t* RowBuffer(uint32_t aRow);
-  void PropagatePassToDownscaler(Downscaler& aDownscaler);
-
-private:
-  uint32_t RowSize() const;
-
-  nsIntSize mImageSize;
-  UniquePtr<uint8_t[]> mBuffer;
-};
 
 } // namespace image
 } // namespace mozilla
diff --git a/image/decoders/nsGIFDecoder2.h b/image/decoders/nsGIFDecoder2.h
index 76ddf1ac2230..952c6015a6aa 100644
--- a/image/decoders/nsGIFDecoder2.h
+++ b/image/decoders/nsGIFDecoder2.h
@@ -8,7 +8,7 @@
 #define mozilla_image_decoders_nsGIFDecoder2_h
 
 #include "Decoder.h"
-
+#include "Deinterlacer.h"
 #include "GIF2.h"
 #include "nsCOMPtr.h"
 
diff --git a/image/moz.build b/image/moz.build
index cf4d51368ec5..7d92a204c331 100644
--- a/image/moz.build
+++ b/image/moz.build
@@ -54,6 +54,7 @@ UNIFIED_SOURCES += [
     'DecodePool.cpp',
     'Decoder.cpp',
     'DecoderFactory.cpp',
+    'Deinterlacer.cpp',
     'DynamicImage.cpp',
     'FrameAnimator.cpp',
     'FrozenImage.cpp',