Change SkImageDecoders to take an SkStreamRewindable.

src/images/SkImageDecoder_libico.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorPriv.h"
 #include "SkImageDecoder.h"
 #include "SkStream.h"
@@ skipping 365 matching lines @@
     alphaBit = 0;
 #endif
     int alpha = readByte(buf, xorOffset + 4*pixelNo + 3) & ((alphaBit-1)&0xFF);
     *address = SkPreMultiplyARGB(alpha, red, green, blue);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 DEFINE_DECODER_CREATOR(ICOImageDecoder);
 /////////////////////////////////////////////////////////////////////////////////////////
 
-static bool is_ico(SkStream* stream) {
+static bool is_ico(SkStreamRewindable* stream) {
     // Check to see if the first four bytes are 0,0,1,0
     // FIXME: Is that required and sufficient?
     SkAutoMalloc autoMal(4);
     unsigned char* buf = (unsigned char*)autoMal.get();
     stream->read((void*)buf, 4);
     int reserved = read2Bytes(buf, 0);
     int type = read2Bytes(buf, 2);
     if (reserved != 0 || type != 1) {
         // This stream does not represent an ICO image.
         return false;
     }
     return true;
 }
 
-static SkImageDecoder* sk_libico_dfactory(SkStream* stream) {
+static SkImageDecoder* sk_libico_dfactory(SkStreamRewindable* stream) {
     if (is_ico(stream)) {
         return SkNEW(SkICOImageDecoder);
     }
     return NULL;
 }
 
 static SkImageDecoder_DecodeReg gReg(sk_libico_dfactory);
 
-static SkImageDecoder::Format get_format_ico(SkStream* stream) {
+static SkImageDecoder::Format get_format_ico(SkStreamRewindable* stream) {
     if (is_ico(stream)) {
         return SkImageDecoder::kICO_Format;
     }
     return SkImageDecoder::kUnknown_Format;
 }
 
 static SkImageDecoder_FormatReg gFormatReg(get_format_ico);