Revert of Teach Skia to use discardable memory

Source/platform/graphics/ImageFrameGenerator.h

Index: Source/platform/graphics/ImageFrameGenerator.h
diff --git a/Source/platform/graphics/ImageFrameGenerator.h b/Source/platform/graphics/ImageFrameGenerator.h
index 32817b48a6790cadf295c65ce5699a8a87ead421..964b0937ebfb2980e315d98610e8440b6b67ea8a 100644
--- a/Source/platform/graphics/ImageFrameGenerator.h
+++ b/Source/platform/graphics/ImageFrameGenerator.h
@@ -66,13 +66,6 @@
 
     const ScaledImageFragment* decodeAndScale(const SkISize& scaledSize, size_t index = 0);
 
-    // Decodes and scales the specified frame indicated by |index|. Dimensions
-    // and output format are specified in |info|. Decoded pixels are written
-    // into |pixels| with a stride of |rowBytes|.
-    //
-    // Returns true if decoding was successful.
-    bool decodeAndScale(const SkImageInfo&, size_t index, void* pixels, size_t rowBytes);
-
     void setData(PassRefPtr<SharedBuffer>, bool allDataReceived);
 
     // Creates a new SharedBuffer containing the data received so far.