Remove bitmap reuse from SkImageDecoder.

Remove bitmap reuse from SkImageDecoder.

Now that Android is using an SkBitmap::Allocator to reuse bitmap
memory, remove the unnecessary code to handle bitmap reuse inside
the decoders themselves.

Leaves in the code for bitmap reuse in decodeSubset, which still
may reuse bitmaps, and cropBitmap, which is called by decodeSubset.

R=djsollen@google.com

Committed: https://code.google.com/p/skia/source/detail?r=9931

[djsollen, 2013-06-26 11:56:45]

lgtm with one nit.

https://codereview.chromium.org/17620004/diff/1/include/core/SkImageDecoder.h
File include/core/SkImageDecoder.h (right):

https://codereview.chromium.org/17620004/diff/1/include/core/SkImageDecoder.h...
include/core/SkImageDecoder.h:222: note: document use of Allocator, Peeker and
Chooser
can you add info here on how they can use the allocator for bitmap reuse?

[scroggo, 2013-06-26 15:35:28]

New patch with comments.

https://codereview.chromium.org/17620004/diff/1/include/core/SkImageDecoder.h
File include/core/SkImageDecoder.h (right):

https://codereview.chromium.org/17620004/diff/1/include/core/SkImageDecoder.h...
include/core/SkImageDecoder.h:222: note: document use of Allocator, Peeker and
Chooser
On 2013/06/26 11:56:45, djsollen wrote:
> can you add info here on how they can use the allocator for bitmap reuse?

How does the new comment sound? Since bitmap reuse is fairly complicated, I'd
rather not put a full explanation of how to do it. On the other hand, I don't
want a caller to interpret the comment to mean that it's simple and do something
incorrectly.

[djsollen, 2013-06-26 15:54:01]

lgtm.  I think that covers it at the correct level of detail.

[scroggo, 2013-07-09 15:45:19]

Committed patchset #2 manually as r9931 (presubmit successful).