Support for HW JPEG Decoder in SKIA

Add support to use HW JPEG Decoder in SKIA
through dynamic loading of vendor specific
library. Vendor library to provide APIs to
check if HW decode is possible for a stream
and if so decode the stream. Methods
allocPixelRef and getPrefConfig in
SkImageDecoder made public because vendor
lib has access only to the SkImageDecoder
and not its derived class.

Change-Id: Ie6e9366603a3a3923d7f041d7601589dadf75ac8
ARM Skia NEON patches - 20 - New improved BitmapProcState code

BitmapProcState: new factorised code

This one basically factorises the clamp and repeat transformations with
some performance improvements. It has the benefit of being faster, much
easier to maintain (nearly three times less code for more work
done :-)), and more complete (all persp transformations weren't optimised
in the previous version).

It also introduces the use of can_truncate_to_fixed_for_decal where
useful.

The effect on benchmarks ranges from a 5% penalty to a 25% gain on a
Cortex-A9 and from a 5% penalty to a 100% gain on a Cortex-A15.

Signed-off-by: Kévin PETIT <kevin.petit@arm.com>

BUG=
R=djsollen@google.com, mtklein@google.com, luisjoseromeroesclusa@hotmail.com, reed@google.com

Author: kevin.petit.arm@gmail.com

Review URL: https://codereview.chromium.org/23835006

Change-Id: Ifb1a610730548f6e487dbb60bebcf69150186ed1
git-svn-id: http://skia.googlecode.com/svn/trunk@13218 2bbb7eff-a529-9590-31e7-b0007b416f81