Roll src/third_party/libvpx/source/libvpx/ 4d4231352..8121f8547 (17 commits).

third_party/libvpx/source/config/linux/x64/vpx_dsp_rtcd.h

Index: third_party/libvpx/source/config/linux/x64/vpx_dsp_rtcd.h
diff --git a/third_party/libvpx/source/config/linux/x64/vpx_dsp_rtcd.h b/third_party/libvpx/source/config/linux/x64/vpx_dsp_rtcd.h
index ac714cabf6f968726aa26a5dd4fae717c6ca8a96..df2e81e79b2f3bfb124c0adc62eb21782362af46 100644
--- a/third_party/libvpx/source/config/linux/x64/vpx_dsp_rtcd.h
+++ b/third_party/libvpx/source/config/linux/x64/vpx_dsp_rtcd.h
@@ -1488,7 +1488,8 @@ void vpx_idct8x8_1_add_sse2(const tran_low_t *input, uint8_t *dest, int stride);
 
 void vpx_idct8x8_64_add_c(const tran_low_t *input, uint8_t *dest, int stride);
 void vpx_idct8x8_64_add_sse2(const tran_low_t *input, uint8_t *dest, int stride);
-#define vpx_idct8x8_64_add vpx_idct8x8_64_add_sse2
+void vpx_idct8x8_64_add_ssse3(const tran_low_t *input, uint8_t *dest, int stride);
+RTCD_EXTERN void (*vpx_idct8x8_64_add)(const tran_low_t *input, uint8_t *dest, int stride);
 
 int16_t vpx_int_pro_col_c(const uint8_t *ref, const int width);
 int16_t vpx_int_pro_col_sse2(const uint8_t *ref, const int width);
@@ -2155,6 +2156,8 @@ static void setup_rtcd_internal(void)
     if (flags & HAS_SSSE3) vpx_idct32x32_34_add = vpx_idct32x32_34_add_ssse3;
     vpx_idct8x8_12_add = vpx_idct8x8_12_add_sse2;
     if (flags & HAS_SSSE3) vpx_idct8x8_12_add = vpx_idct8x8_12_add_ssse3;
+    vpx_idct8x8_64_add = vpx_idct8x8_64_add_sse2;
+    if (flags & HAS_SSSE3) vpx_idct8x8_64_add = vpx_idct8x8_64_add_ssse3;
     vpx_lpf_horizontal_16 = vpx_lpf_horizontal_16_sse2;
     if (flags & HAS_AVX2) vpx_lpf_horizontal_16 = vpx_lpf_horizontal_16_avx2;
     vpx_lpf_horizontal_16_dual = vpx_lpf_horizontal_16_dual_sse2;