libvpx: Pull from upstream

libvpx: Pull from upstream

configuration changes:
Disable avx2 automatically.
Build vp9 encoder.

Current HEAD: 4aaf4841f2ddfee3860087dabebf7173dc4f0708

git log from upstream:
5260b39 vpxdec: restoring old md5 behavior for y4m files.
ff41764 Removing _1d suffix from transform names.
770454f Add vp9_tm_predictor_32x32 neon implementation which is 7.8 times faster than C.
e5b31a1 Decoupling set_ref_ptrs() and vp9_setup_interp_filters().
7ec2769 Adapting simple_decoder to use new file reading API.
6f00a46 Ouput symbols as c header file.
05d2081 Fix the vp9_tm_predictor_8x8_neon.
cacea00 Adds a stand-alone resize utility for testing
1a8394f Multiple resize filters
b93fcec Adding get_bsize() function to vp9_firstpass.c.
c0214e7 Cache loop filter errors.
8c2ae2d Refactor loop filter level search.
8691565 Removing subpix_fn_table struct.
a0b9b05 Added a speed feature
4264c93 Renaming INTERPOLATION_TYPE to INTERP_FILTER.
ea283a6 Add some consts to vp9_calc_ss_err().
f7ddbeb Removing unused inter_mode_counts field from CODING_CONTEXT.
8971338 change to avoid IOC
4ce8929 Add a method to estimate loop filter level from quantizer and frame type.
e5034f6 Fixed integer overflow for large input video
c2b3368 Implementing simple API to read video files.
4bc1877 Cleaning up vp9_ratectl.c file.
abf37f1 Inlining IFMVCV macro.
56a8a0b Optimize vp9_tm_predictor_8x8_neon function
3633ffc Add vp9_tm_predictor_16x16 neon implementation which is 3.5 times faster than C.
b1c72b6 Revert external frame buffer code.
002ad40 test/: remove unnecessary extern "C"s
<...>

TBR=tomfinegan@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=247516

[Johann, 2014-01-28 23:01:13]

Committed patchset #1 manually as r247516 (presubmit successful).

[Tom Finegan, 2014-01-28 23:10:41]

lgtm

[Tom Finegan, 2014-01-28 23:10:47]

lgtm