Properly store the tx_size of selected intra mode

Use a temporary variable to store the transform size associated
with the best intra mode and restore the mode_info if the overall
best mode is intra mode.

Change-Id: I2606e0061ad32f91b095462902b1eb734b128eea
Rework mode search threshold update for RTC coding mode

In RTC coding mode, the alternate reference frame modes and compound
inter prediction modes are disabled. This commit reworks the
related mode search threshold update process to skip interacting
with these coding modes. It provides about 1.5% speed-up for speed
-6 on average.

vidyo1
16551 b/f, 40.451 dB, 6261 ms -> 16550 b/f, 40.459 dB, 6190 ms

nik720p
33316 b/f, 38.795 dB, 6335 ms -> 33310 b/f, 38.798 dB, 6237 ms

mmmoving
33265 b/f, 41.055 dB, 7176 ms -> 33267 b/f, 41.064 dB, 7084 ms

dark720
33329 b/f, 39.729 dB, 11235 ms -> 33331 b/f, 39.733 dB, 10731 ms

Change-Id: If2a4090a371cd28f579be219c013b972d7d9b97f
Remove ARF mode entries from THR_MODES array in non-RD mode

The alternate reference frame is disabled in non-RD mode. No need
to keep the related entries in the THR_MODES array.

Change-Id: I53386f4bb1c6284f582801f27246c5edf55bc24b
vpxdec: ignore GET_FRAME_CORRUPTED error w/--keep-going

this function may return an error if no frame is available; --keep-going
is meant to test decoder resilience, so simply warn in this case.

Change-Id: I6e6aed3e78eca21cca80d7d8a06a1a244685ba29
Add a guard on intra mode skip control for RTC mode

This commit adds a guard condition to the intra mode test skip
control in RTC coding mode. If all inter modes are skipped, force
the encoder to check intra mode. It avoids situations where the
encoder processes without properly assigning required mode
information.

Change-Id: Ibb349fee997d6584ce901d08b06e8df3ca9c01b1
vp9_ethread: add the multi-threaded encoder unit tests

The unit tests for VP9 multi-threaded encoder are added, which
carry out tests for all three modes(i.e. kTwoPassGood, kOnePassGood
and kRealTime), and speeds ranging from 1 to 8. A 1280x720 test
clip is used, which is encoded into multiple tiles. The number of
threads is num_of_tiles.

Change-Id: I04419eeca145ad841c9c527603668239a82e7fbd
Merge "Properly store the tx_size of selected intra mode"
Merge "Rework mode search threshold update for RTC coding mode"
Merge "Remove ARF mode entries from THR_MODES array in non-RD mode"
Merge "Add a guard on intra mode skip control for RTC mode"
Merge "vpxdec: ignore GET_FRAME_CORRUPTED error w/--keep-going"
Merge "vp9_ethread: add the multi-threaded encoder unit tests"