Updates to images project.

Use the SkImageEncoder_Factory on all platforms. On Windows and Mac,
register the platform's image encoder as an option for
SkImageEncoder::Create. Also add more types that can be decoded.

Update comments for SkImageDecoder to be more accurate.

Add more types to SkImageEncoder::Type, and return the correct type of
encoder, if it exists.

Use a custom version of SkImageDecoder::Factory on Windows and Mac to
check the stream for registered decoders before defaulting to the platform's
version. Share code with the existing SkImageDecoder::Factory method.

Preparation for testing decoders and encoders:
BUG=https://code.google.com/p/skia/issues/detail?id=1241

Review URL: https://codereview.chromium.org/14298010

git-svn-id: http://skia.googlecode.com/svn/trunk@8730 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/images/SkImageDecoder_FactoryDefault.cpp b/src/images/SkImageDecoder_FactoryDefault.cpp
new file mode 100644
index 0000000..565519a
--- /dev/null
+++ b/src/images/SkImageDecoder_FactoryDefault.cpp
@@ -0,0 +1,37 @@
+
+/*
+ * 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.h"
+#include "SkMovie.h"
+#include "SkStream.h"
+#include "SkTRegistry.h"
+
+extern SkImageDecoder* image_decoder_from_stream(SkStream*);
+
+SkImageDecoder* SkImageDecoder::Factory(SkStream* stream) {
+    return image_decoder_from_stream(stream);
+}
+
+/////////////////////////////////////////////////////////////////////////
+
+typedef SkTRegistry<SkMovie*, SkStream*> MovieReg;
+
+SkMovie* SkMovie::DecodeStream(SkStream* stream) {
+    const MovieReg* curr = MovieReg::Head();
+    while (curr) {
+        SkMovie* movie = curr->factory()(stream);
+        if (movie) {
+            return movie;
+        }
+        // we must rewind only if we got NULL, since we gave the stream to the
+        // movie, who may have already started reading from it
+        stream->rewind();
+        curr = curr->next();
+    }
+    return NULL;
+}