Consistent update for inter_mode probabilities.

Using inter-mode counts instead of inter-mode-tree branch counts inside
FRAME_COUNTS structure.

Change-Id: I60dde13af37d06146d7d15543311c1b5044e9e04
Make the use of ref_frame index consistent

Refactor the frame buffer referencing in choose_partition and make
it consistent with other places. This means to prevent potential
issues when we extend reference frame buffer.

Change-Id: I5ff33ed5f671e1f4cc7049622212769a9b4578d9
Merge "Make the use of ref_frame index consistent"
Removing unused "ishp" arguments.

Using different variable names "allow_hp" and "use_hp" instead of "usehp".

Change-Id: I0cd5996ddeb46bd754473b680a993c0aaf8eb879
Merge "Consistent update for inter_mode probabilities."
Merge "Removing unused "ishp" arguments."
Removing get_mi_{row, col} functions.

Passing mi_row and mi_col parameters to functions explicitly. Removing
unused xd argument from scale_mv function.

Change-Id: Icb4c495ec72d26fb066c14470d3ae0b741fbf18a
vp9_decodemv.c cleanup.

Inlining VP9_NMV_UPDATE_PROB constant, consistent local variable names.

Change-Id: I01692501982568fa535882d6b320e3c692f88abb
Remove unnecessary arguments in rd_pick_ref_frame

This commit removes redundant arguments passing in the function of
rd_pick_reference_frame. This resolves the clang warnings about
potential use of uninitialized values.

Change-Id: Ic68f949a9f8fcd0a583786b0c75321104ea44739
Optimize 32x32 2D inverse DCT for speed-up

This commit exploits the sparsity of quantized coefficient matrix.
It detects each 32x8 array and skip the corresponding inverse
transformation if all entries are zero.

For ped1080p at 8000 kbps, this on average reduces the runtime of
32x32 inverse 2D-DCT SSE2 function from 6256 cycles -> 5200
cycles. It makes the overall encoding process about 2% faster at
speed 0. The speed-up is more pronounceable for the decoding process.

Change-Id: If20056c3566bd117642a76f8884c83e8bc8efbcf
vp9_get_pred_context_intra_inter cleanup.

Change-Id: I8beeee4c020425175f7d5ec83be86afa7b95da1a
Adding missing const to vp9_extra_bits array.

Change-Id: Icd128ab58719e0b9066bdfa66a5d0d427a84d6df
Changed name of rd_pick_intra4x4mby_modes

The function name rd_pick_intra4x4mby_modes is confusing, so
I changed it to rd_pick_intra_sub_8x8_y_modes to better
reflect what the function does. Also added const qualifiers
to some of the input parameters and removed camel-case.

Change-Id: I23d53d4c7af5d79ed8a471acd59a09bbb47add39
Fixed typos and added a few explanatory comments

Change-Id: Ib4e4b41094b54874ee34343dd77c0c131ceed9d2
Merge "Adding missing const to vp9_extra_bits array."
Comment out 2 unused speed features

use_min_partition_size and use_max_partition_size are not used
currently, and could be added back if needed later.

Change-Id: Ib22a9c06b064567a7c1d6d5445567ed77e0d3acc
Add more checking to using_small_partition_info

If the partition is out of partition size range, we don't
need to process small partition information.

Change-Id: Ice9bfbbdebe1f2ef79271a3aee17de0ed4608376
Merge "Optimize 32x32 2D inverse DCT for speed-up"
Remove unused vp9_short_idct10_32x32_add

The inverse 32x32 transform detects all zero entries and skips the
computations accordingly per 8 rows in the first 1-D operation. The
function vp9_short_idct10_32x32_add performs differently and is not
used anywhere, hence removed.

Change-Id: Ic4fad422debbde7b6b6ffed47c69fbd4268a906c
Adds a source variance computation function

Adds a function to compute source variance for various
sb_types to be used for pruning mode and partition searches.
[The existing activity measure function is currently specialized
for only 16x16 MBs and needs to be updated].

Change-Id: I22a41e6f1430184201487326fdbebb9b47e6fc24