Change SkImageDecoders to take an SkStreamRewindable.

src/images/SkMovie_gif.cpp

Index: src/images/SkMovie_gif.cpp
diff --git a/src/images/SkMovie_gif.cpp b/src/images/SkMovie_gif.cpp
index 315816812a6238a0e4cd2db549b664eaa001f563..441626bf64c6654b6926d7e86bfc9820a1de1ab1 100644
--- a/src/images/SkMovie_gif.cpp
+++ b/src/images/SkMovie_gif.cpp
@@ -18,7 +18,7 @@
 
 class SkGIFMovie : public SkMovie {
 public:
-    SkGIFMovie(SkStream* stream);
+    SkGIFMovie(SkStreamRewindable* stream);
     virtual ~SkGIFMovie();
 
 protected:
@@ -34,11 +34,11 @@ private:
 };
 
 static int Decode(GifFileType* fileType, GifByteType* out, int size) {
-    SkStream* stream = (SkStream*) fileType->UserData;
+    SkStreamRewindable* stream = (SkStreamRewindable*) fileType->UserData;
     return (int) stream->read(out, size);
 }
 
-SkGIFMovie::SkGIFMovie(SkStream* stream)
+SkGIFMovie::SkGIFMovie(SkStreamRewindable* stream)
 {
 #if GIFLIB_MAJOR < 5
     fGIF = DGifOpen( stream, Decode );
@@ -432,7 +432,7 @@ bool SkGIFMovie::onGetBitmap(SkBitmap* bm)
 
 #include "SkTRegistry.h"
 
-SkMovie* Factory(SkStream* stream) {
+SkMovie* Factory(SkStreamRewindable* stream) {
     char buf[GIF_STAMP_LEN];
     if (stream->read(buf, GIF_STAMP_LEN) == GIF_STAMP_LEN) {
         if (memcmp(GIF_STAMP,   buf, GIF_STAMP_LEN) == 0 ||
@@ -446,4 +446,4 @@ SkMovie* Factory(SkStream* stream) {
     return NULL;
 }
 
-static SkTRegistry<SkMovie*, SkStream*> gReg(Factory);
+static SkTRegistry<SkMovie*, SkStreamRewindable*> gReg(Factory);