Fix iOS build.

More SkStream -> SkStreamRewindable.

git-svn-id: http://skia.googlecode.com/svn/trunk@11463 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/utils/ios/SkImageDecoder_iOS.mm b/src/utils/ios/SkImageDecoder_iOS.mm
index 77d49a5..f347e06 100755
--- a/src/utils/ios/SkImageDecoder_iOS.mm
+++ b/src/utils/ios/SkImageDecoder_iOS.mm
@@ -54,11 +54,11 @@
 
 /////////////////////////////////////////////////////////////////////////
 
-SkImageDecoder* SkImageDecoder::Factory(SkStream* stream) {
+SkImageDecoder* SkImageDecoder::Factory(SkStreamRewindable* stream) {
     return new SkImageDecoder_iOS;
 }
 
-SkMovie* SkMovie::DecodeStream(SkStream* stream) {
+SkMovie* SkMovie::DecodeStream(SkStreamRewindable* stream) {
     return NULL;
 }