libvpx: Pull from upstream

libvpx: Pull from upstream

Current HEAD: 3a5d40608ef5603764f45ec33448f5c013b875b4

git log from upstream:
ba18609 Remove unnecessary pointer check
65a1a3e adjust rtc setting and threshold
eabb793 Use correct buffer size in vp8 subpixel variance
e8c42fb Remove duplicate code.
9f1cf2c make low bitrates a lot less blocky
ca9c352 Assign 2nd ref frame in choose_partitioning
852829c Fail when only an old nasm is found
85a9bc0 vp9_dthread: pass frame counts to decoder functions
a6b3e01 Add mutex initialization in encoder
39a74e1 Ensure the error-concealment code is available
94a4595 Fix a bug from merging frame parallel branch into master.
b50e518 Require webm when explicitly requested
797a255 Allow larger encoder configurations.
f92c0b1 Abort if firstpass file does not exist
45971ab Optimize coef update
be6aead Try again to merge branch 'frame-parallel' into master branch.
f6c2a6c vp9: rename 'near' parameters
9bdc0ae Format fixes in vp9_rd_pick_inter_mode_sb/sub8x8
ef7f33b configure: echo --(disable|enable)-* cmdline options
04168d4 Explicitly include vp8_rtcd.h
cc7fac3 Enable use_x86inc for 32bit pic enabled Darwin target
10d5e09 Fix issues in 32bit PIC enabled build
f752da8 Change to update of rate control factors.
c0923d4 Fix to vp9 denoiser.
ff99a3c Simplify update_coef_probs()
581731a vp8enc: Prevent out of bounds memory access.
e3167f7 Add vp9_sad32x32x4d_neon Neon intrinsic function.
9f574d0 Add vp9_sad16x16x4d_neon Neon intrinsic function.
54fa956 Add vp9_sad64x64x4d_neon Neon intrinsic function.
645b7cd move clear_system_state() call before using double
ad314c1 Fix discovery of Darwin SDKs
3f1af6e aq-mode=3: Update to allow for refresh on modes other than zero-mv.
fd07022 Adjust active maxq for GF groups.
6d16f6c Fix MSVC warnings on conversion from int64 to int
1387f4d iosbuild.sh: Increase build speed.
9f6eba4 Add Neon intrinsic vp9_fdct8x8_quant_neon
eda1797 Replace divide with look-up
4ed1bda x86: correct OSXSAVE + AVX bit check
<...>

TBR=tomfinegan@chromium.org
BUG=webrtc:4190
Committed: 4a7d50a9624d84473904d9c9bf43f2fe502aa94a

[Johann, 2015-02-04 17:38:29]

Committed patchset #1 (id:1) manually as
4a7d50a9624d84473904d9c9bf43f2fe502aa94a (presubmit successful).

[Tom Finegan, 2015-02-04 17:55:24]

lgtm