codec: Enable VP9 row multithread encoding.

Bug:69864768
Test: None
Change-Id: I1bcffccac7cca0e0f11dd21b1cb666b3772b8672
diff --git a/media/libstagefright/codecs/on2/enc/SoftVP9Encoder.cpp b/media/libstagefright/codecs/on2/enc/SoftVP9Encoder.cpp
index 4c7290d..1ea1c85 100644
--- a/media/libstagefright/codecs/on2/enc/SoftVP9Encoder.cpp
+++ b/media/libstagefright/codecs/on2/enc/SoftVP9Encoder.cpp
@@ -69,6 +69,13 @@
               codecReturn);
         return codecReturn;
     }
+    codecReturn = vpx_codec_control(mCodecContext, VP9E_SET_ROW_MT, 1);
+    if (codecReturn != VPX_CODEC_OK) {
+        ALOGE("Error setting VP9E_SET_ROW_MT to 1. vpx_codec_control() "
+              "returned %d", codecReturn);
+        return codecReturn;
+    }
+
     // For VP9, we always set CPU_USED to 8 (because the realtime default is 0
     // which is too slow).
     codecReturn = vpx_codec_control(mCodecContext, VP8E_SET_CPUUSED, 8);