decode_api_test: fix type conversion warning

size_t -> uint32 in the call to vpx_codec_decode()

Change-Id: Ibf39d3749321c97292b35ac0631fa22211cff800

test/decode_api_test.cc

@@ -112,9 +112,9 @@ TEST(DecodeAPI, Vp9InvalidDecode) {
 
   vpx_codec_ctx_t dec;
   EXPECT_EQ(VPX_CODEC_OK, vpx_codec_dec_init(&dec, codec, NULL, 0));
+  const uint32_t frame_size = static_cast<uint32_t>(video.frame_size());
   EXPECT_EQ(VPX_CODEC_MEM_ERROR,
-            vpx_codec_decode(&dec, video.cxdata(), video.frame_size(), NULL,
-                             0));
+            vpx_codec_decode(&dec, video.cxdata(), frame_size, NULL, 0));
   vpx_codec_iter_t iter = NULL;
   EXPECT_EQ(NULL, vpx_codec_get_frame(&dec, &iter));