Add the lazy decoder from PictureFlags to SkImageDecoder

tools/LazyDecodeBitmap.h

Index: tools/LazyDecodeBitmap.h
diff --git a/tools/LazyDecodeBitmap.h b/tools/LazyDecodeBitmap.h
new file mode 100644
index 0000000000000000000000000000000000000000..ea7e35256a58e5d4f66c527071ec5b33c953fb75
--- /dev/null
+++ b/tools/LazyDecodeBitmap.h
@@ -0,0 +1,16 @@
+/*
+ * Copyright 2006 The Android Open Source Project

[scroggo, 2013/07/15 18:02:41]

2013

+ *
+ * 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"
+#include "SkBitmap.h"

[scroggo, 2013/07/15 18:02:41]

SkBitmap can be forward-declared here, and included in the implementation file.

[sglez, 2013/07/16 15:59:33]

It compiles with just the forward declaration. Some other header must be
including SkBitmap.

[scroggo, 2013/07/16 16:06:18]

Although the forward declaration is enough to compile, it is better practice to
include the things you use. If the include chain ceases to include SkBitmap.h,
you'll get a break here without changing LazyDecodeBitmap directly. Please add
#include "SkBitmap.h" in LazyDecodeBitmap.cpp.

+

[scroggo, 2013/07/15 18:02:41]

Maybe add a comment here, explaining its purpose. The current implementation is
intertwined with PictureRenderingFlags and SkCommandLineFlags, which is not
currently obvious by looking at the header.

+bool LazyDecodeBitmap(const void* buffer, size_t size, SkBitmap* bitmap);

[scroggo, 2013/07/15 18:02:41]

This should go inside a class or namespace. It could go in the namespace for
sk_tools, or something more specific to bitmap decoding.

+
+#endif  // LazyDecodeBitmap_DEFINED