Remove image decoder and encoder autoregistration

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 "SkImageDecoder_libico.h"
 #include "SkColorPriv.h"
 #include "SkImageDecoder.h"
 #include "SkStream.h"
 #include "SkStreamPriv.h"
 #include "SkTypes.h"
 
 class SkICOImageDecoder : public SkImageDecoder {
 public:
     SkICOImageDecoder();
 
@@ skipping 373 matching lines @@
     int green = readByte(buf, xorOffset + 4*pixelNo + 1);
     int red = readByte(buf, xorOffset + 4*pixelNo + 2);
     int alphaBit = (alphaByte & m) >> shift;
 #if 1 // don't trust the alphaBit for 32bit images <mrr>
     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(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;
+    if (0 != reserved || 1 != type) {
+        return SkImageDecoder::kUnknown_Format;
+    }
+    return SkImageDecoder::kICO_Format;
 }
 
-static SkImageDecoder* sk_libico_dfactory(SkStreamRewindable* stream) {
-    if (is_ico(stream)) {
-        return SkNEW(SkICOImageDecoder);
-    }
-    return NULL;
+SkImageDecoder* SkCreateICOImageDecoder(SkImageDecoder::Format format) {
+    SkASSERT(SkImageDecoder::kICO_Format == format);
+    return SkNEW(SkICOImageDecoder);
 }
 
-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;
-}
-
-static SkImageDecoder_FormatReg gFormatReg(get_format_ico);