diff --git a/image/DecoderFactory.cpp b/image/DecoderFactory.cpp
index 951b188a1740..ad451c9831f8 100644
--- a/image/DecoderFactory.cpp
+++ b/image/DecoderFactory.cpp
@@ -10,6 +10,7 @@
 #include "nsString.h"
 
 #include "Decoder.h"
+#include "IDecodingTask.h"
 #include "nsPNGDecoder.h"
 #include "nsGIFDecoder2.h"
 #include "nsJPEGDecoder.h"
@@ -104,7 +105,7 @@ DecoderFactory::GetDecoder(DecoderType aType,
   return decoder.forget();
 }
 
-/* static */ already_AddRefed<Decoder>
+/* static */ already_AddRefed<IDecodingTask>
 DecoderFactory::CreateDecoder(DecoderType aType,
                               RasterImage* aImage,
                               SourceBuffer* aSourceBuffer,
@@ -139,10 +140,11 @@ DecoderFactory::CreateDecoder(DecoderType aType,
     return nullptr;
   }
 
-  return decoder.forget();
+  RefPtr<IDecodingTask> task = new DecodingTask(WrapNotNull(decoder));
+  return task.forget();
 }
 
-/* static */ already_AddRefed<Decoder>
+/* static */ already_AddRefed<IDecodingTask>
 DecoderFactory::CreateAnimationDecoder(DecoderType aType,
                                        RasterImage* aImage,
                                        SourceBuffer* aSourceBuffer,
@@ -171,10 +173,11 @@ DecoderFactory::CreateAnimationDecoder(DecoderType aType,
     return nullptr;
   }
 
-  return decoder.forget();
+  RefPtr<IDecodingTask> task = new DecodingTask(WrapNotNull(decoder));
+  return task.forget();
 }
 
-/* static */ already_AddRefed<Decoder>
+/* static */ already_AddRefed<IDecodingTask>
 DecoderFactory::CreateMetadataDecoder(DecoderType aType,
                                       RasterImage* aImage,
                                       SourceBuffer* aSourceBuffer,
@@ -198,7 +201,8 @@ DecoderFactory::CreateMetadataDecoder(DecoderType aType,
     return nullptr;
   }
 
-  return decoder.forget();
+  RefPtr<IDecodingTask> task = new MetadataDecodingTask(WrapNotNull(decoder));
+  return task.forget();
 }
 
 /* static */ already_AddRefed<Decoder>
diff --git a/image/DecoderFactory.h b/image/DecoderFactory.h
index 85bb5ec0b1aa..d41c9facbf18 100644
--- a/image/DecoderFactory.h
+++ b/image/DecoderFactory.h
@@ -20,6 +20,7 @@ namespace mozilla {
 namespace image {
 
 class Decoder;
+class IDecodingTask;
 class RasterImage;
 class SourceBuffer;
 
@@ -64,7 +65,7 @@ public:
    * @param aSampleSize The sample size requested using #-moz-samplesize (or 0
    *                    if none).
    */
-  static already_AddRefed<Decoder>
+  static already_AddRefed<IDecodingTask>
   CreateDecoder(DecoderType aType,
                 RasterImage* aImage,
                 SourceBuffer* aSourceBuffer,
@@ -86,7 +87,7 @@ public:
    * @param aSurfaceFlags Flags specifying the type of output this decoder
    *                      should produce.
    */
-  static already_AddRefed<Decoder>
+  static already_AddRefed<IDecodingTask>
   CreateAnimationDecoder(DecoderType aType,
                          RasterImage* aImage,
                          SourceBuffer* aSourceBuffer,
@@ -107,7 +108,7 @@ public:
    * @param aSampleSize The sample size requested using #-moz-samplesize (or 0
    *                    if none).
    */
-  static already_AddRefed<Decoder>
+  static already_AddRefed<IDecodingTask>
   CreateMetadataDecoder(DecoderType aType,
                         RasterImage* aImage,
                         SourceBuffer* aSourceBuffer,
diff --git a/image/IDecodingTask.h b/image/IDecodingTask.h
index 0e60683ae3c9..bc2b2fe35a66 100644
--- a/image/IDecodingTask.h
+++ b/image/IDecodingTask.h
@@ -47,6 +47,9 @@ public:
   /// DecodePool. Subclasses can override this if they need different behavior.
   void Resume() override;
 
+  /// @return a non-null weak pointer to the Decoder associated with this task.
+  virtual NotNull<Decoder*> GetDecoder() const = 0;
+
   // Notify the Image associated with a Decoder of its progress, sending a
   // runnable to the main thread if necessary.
   // XXX(seth): This is a hack that will be removed soon.
@@ -74,6 +77,8 @@ public:
   // don't block layout or page load.
   TaskPriority Priority() const override { return TaskPriority::eLow; }
 
+  NotNull<Decoder*> GetDecoder() const override { return mDecoder; }
+
 private:
   virtual ~DecodingTask() { }
 
@@ -102,6 +107,8 @@ public:
   // page load.
   TaskPriority Priority() const override { return TaskPriority::eHigh; }
 
+  NotNull<Decoder*> GetDecoder() const override { return mDecoder; }
+
 private:
   virtual ~MetadataDecodingTask() { }
 
@@ -130,6 +137,8 @@ public:
   // matter what, we don't want to resume by posting a task to the DecodePool.
   void Resume() override { }
 
+  NotNull<Decoder*> GetDecoder() const override { return mDecoder; }
+
 private:
   virtual ~AnonymousDecodingTask() { }
 
diff --git a/image/RasterImage.cpp b/image/RasterImage.cpp
index e1a0d30921a0..7d13d44f38da 100644
--- a/image/RasterImage.cpp
+++ b/image/RasterImage.cpp
@@ -1306,30 +1306,31 @@ RasterImage::Decode(const IntSize& aSize, uint32_t aFlags)
   }
 
   // Create a decoder.
-  RefPtr<Decoder> decoder;
+  RefPtr<IDecodingTask> task;
   if (mAnim) {
-    decoder = DecoderFactory::CreateAnimationDecoder(mDecoderType, this,
-                                                     mSourceBuffer, decoderFlags,
-                                                     surfaceFlags);
+    task = DecoderFactory::CreateAnimationDecoder(mDecoderType, this,
+                                                  mSourceBuffer, decoderFlags,
+                                                  surfaceFlags);
   } else {
-    decoder = DecoderFactory::CreateDecoder(mDecoderType, this, mSourceBuffer,
-                                            targetSize, decoderFlags,
-                                            surfaceFlags,
-                                            mRequestedSampleSize);
+    task = DecoderFactory::CreateDecoder(mDecoderType, this, mSourceBuffer,
+                                         targetSize, decoderFlags,
+                                         surfaceFlags,
+                                         mRequestedSampleSize);
   }
 
   // Make sure DecoderFactory was able to create a decoder successfully.
-  if (!decoder) {
+  if (!task) {
     return NS_ERROR_FAILURE;
   }
 
   // Add a placeholder for the first frame to the SurfaceCache so we won't
   // trigger any more decoders with the same parameters.
+  SurfaceKey surfaceKey =
+    RasterSurfaceKey(aSize,
+                     task->GetDecoder()->GetSurfaceFlags(),
+                     /* aFrameNum = */ 0);
   InsertOutcome outcome =
-    SurfaceCache::InsertPlaceholder(ImageKey(this),
-                                    RasterSurfaceKey(aSize,
-                                                     decoder->GetSurfaceFlags(),
-                                                     /* aFrameNum = */ 0));
+    SurfaceCache::InsertPlaceholder(ImageKey(this), surfaceKey);
   if (outcome != InsertOutcome::SUCCESS) {
     return NS_ERROR_FAILURE;
   }
@@ -1337,7 +1338,6 @@ RasterImage::Decode(const IntSize& aSize, uint32_t aFlags)
   mDecodeCount++;
 
   // We're ready to decode; start the decoder.
-  RefPtr<IDecodingTask> task = new DecodingTask(WrapNotNull(decoder));
   LaunchDecodingTask(task, this, aFlags, mHasSourceData);
   return NS_OK;
 }
@@ -1352,17 +1352,16 @@ RasterImage::DecodeMetadata(uint32_t aFlags)
   MOZ_ASSERT(!mHasSize, "Should not do unnecessary metadata decodes");
 
   // Create a decoder.
-  RefPtr<Decoder> decoder =
+  RefPtr<IDecodingTask> task =
     DecoderFactory::CreateMetadataDecoder(mDecoderType, this, mSourceBuffer,
                                           mRequestedSampleSize);
 
   // Make sure DecoderFactory was able to create a decoder successfully.
-  if (!decoder) {
+  if (!task) {
     return NS_ERROR_FAILURE;
   }
 
   // We're ready to decode; start the decoder.
-  RefPtr<IDecodingTask> task = new MetadataDecodingTask(WrapNotNull(decoder));
   LaunchDecodingTask(task, this, aFlags, mHasSourceData);
   return NS_OK;
 }