Remove image decoder and encoder autoregistration

src/images/SkImageDecoder_libico.cpp

Index: src/images/SkImageDecoder_libico.cpp
diff --git a/src/images/SkImageDecoder_libico.cpp b/src/images/SkImageDecoder_libico.cpp
index 5240d09b8672dbdd1980b27bf7d959b8dbcb425f..66e56ce8228593a96b9ae42849cf5e7f1c1f85d1 100644
--- a/src/images/SkImageDecoder_libico.cpp
+++ b/src/images/SkImageDecoder_libico.cpp
@@ -5,6 +5,7 @@
  * found in the LICENSE file.
  */
 
+#include "SkImageDecoder_libico.h"
 #include "SkColorPriv.h"
 #include "SkImageDecoder.h"
 #include "SkStream.h"
@@ -398,36 +399,23 @@ static void editPixelBit32(const int pixelNo, const unsigned char* buf,
     *address = SkPreMultiplyARGB(alpha, red, green, blue);
 }
 
-///////////////////////////////////////////////////////////////////////////////
-DEFINE_DECODER_CREATOR(ICOImageDecoder);
-/////////////////////////////////////////////////////////////////////////////////////////
-
-static bool is_ico(SkStreamRewindable* stream) {
+SkImageDecoder::Format SkDetectFormatICOImageDecoder(SkStreamRewindable* stream) {
     // Check to see if the first four bytes are 0,0,1,0
     // FIXME: Is that required and sufficient?
     char buf[4];
     if (stream->read((void*)buf, 4) != 4) {
-        return false;
+        return SkImageDecoder::kUnknown_Format;
     }
     int reserved = read2Bytes(buf, 0);
     int type = read2Bytes(buf, 2);
-    return 0 == reserved && 1 == type;
-}
-
-static SkImageDecoder* sk_libico_dfactory(SkStreamRewindable* stream) {
-    if (is_ico(stream)) {
-        return SkNEW(SkICOImageDecoder);
+    if (0 != reserved || 1 != type) {
+        return SkImageDecoder::kUnknown_Format;
     }
-    return NULL;
+    return SkImageDecoder::kICO_Format;
 }
 
-static SkImageDecoder_DecodeReg gReg(sk_libico_dfactory);
-
-static SkImageDecoder::Format get_format_ico(SkStreamRewindable* stream) {
-    if (is_ico(stream)) {
-        return SkImageDecoder::kICO_Format;
-    }
-    return SkImageDecoder::kUnknown_Format;
+SkImageDecoder* SkCreateICOImageDecoder(SkImageDecoder::Format format) {
+    SkASSERT(SkImageDecoder::kICO_Format == format);
+    return SkNEW(SkICOImageDecoder);
 }
 
-static SkImageDecoder_FormatReg gFormatReg(get_format_ico);