Allow for 4x4 prediction blocks for key frame, speed 6.

For key frame under variance source partition: 4x4 prediction blocks
may be selected when variance of 8x8 block is very high (threshold is set fairly high for now).

Testing on some RTC clips shows this helps to reduce some ringing artifacts on key frame.
Encoded key frame size increases about ~10%. Key frame PSNR increases about ~0.1-0.2dB.

Change-Id: I56e203fac32ea6ef69897fb3ea269c59cb50d174
x86_abi_support: set LIBVPX_RAND w/vp9-postproc

set LIBVPX_RAND with --enable-vp9-postproc, previously only the vp8
config was checked. this fixes the build with --disable-postproc.

Change-Id: Ia61baded6aa0e44d6443ae4a3c85915f1054f053
vp9_loopfilter_mmx: remove some unused tables

Change-Id: I964d25cc91c8e4864d73b142d9c7a1b39cb6cfbb
vp9_postproc: remove redundant CONFIG_* checks

the entire module is wrapped in CONFIG_VP9_POSTPROC which is forcibly
enabled with CONFIG_INTERNAL_STATS

+ a similar change in vp9_alloccommon.c

Change-Id: I374993297a9fba5bef2f0b71f984eba42f0995a3
vp9: make postproc members depend on CONFIG_VP9_POSTPROC

Change-Id: Id64218386968cee3132269e4a0572650f20fd980
vp9: move encoder-only member from common

allow_comp_inter_inter VP9_COMMON -> VP9_COMP

Change-Id: I6d9dc25d1cdd7e2ab62f5be69cd9fa883d21dbb6
don't set INLINE to 'always_inline'

INLINE is used quite widely in vp9, this change improves performance
1-2% on most modern platforms.

Change-Id: I8a9974aab89fa588ea4923cc7eaf6199e344a528
Remove redundant loads on 1d8_v8 filter.

This CL showed a modest gain in performance on some systems.

Change-Id: Iad636a89a1a9804ab7a0dea302bf2c6a4d1653a4
Remove redundant loads on 1d16_v8 filter.

This CL showed about a 3% gain in performance on some systems.

Change-Id: Id27e7e0b8e69068aa364e67859436da852669250
Add support for setting byte alignment.

Add support for setting byte alignment on the Y, U, and V plane of the
reference buffers. The byte alignment must be a power of 2, from 32 to
1024. A value of 0 sets legacy alignment.

Change-Id: I7c1399622f7aa68e123646369216b32047dda73d
Merge "x86_abi_support: set LIBVPX_RAND w/vp9-postproc"
Merge "vp9_loopfilter_mmx: remove some unused tables"
Merge "Allow for 4x4 prediction blocks for key frame, speed 6."
Merge changes Id6421838,I37499329

* changes:
  vp9: make postproc members depend on CONFIG_VP9_POSTPROC
  vp9_postproc: remove redundant CONFIG_* checks
Merge "don't set INLINE to 'always_inline'"
Merge "vp9: move encoder-only member from common"
Merge "Remove redundant loads on 1d8_v8 filter."
Merge "Remove redundant loads on 1d16_v8 filter."
Merge "Add support for setting byte alignment."