Add the lazy decoder from PictureFlags to SkImageDecoder

R=caryclark@google.com, scroggo@google.com

Author: sglez@google.com

Review URL: https://chromiumcodereview.appspot.com/19109002

git-svn-id: http://skia.googlecode.com/svn/trunk@10111 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/LazyDecodeBitmap.h b/tools/LazyDecodeBitmap.h
new file mode 100644
index 0000000..ecceb94
--- /dev/null
+++ b/tools/LazyDecodeBitmap.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef LazyDecodeBitmap_DEFINED
+#define LazyDecodeBitmap_DEFINED
+
+#include "SkTypes.h"
+
+class SkBitmap;
+
+namespace sk_tools {
+
+/**
+ * Decode the image with DecodeMemoryToTarget but defer the process until it is needed.
+ */
+bool LazyDecodeBitmap(const void* buffer, size_t size, SkBitmap* bitmap);
+
+}
+
+#endif  // LazyDecodeBitmap_DEFINED