Remove hardcoded kValueSizeBytes values from variable-length header extensions.

webrtc/modules/rtp_rtcp/source/rtp_header_extension_unittest.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_header_extension_unittest.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_header_extension_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtp_header_extension_unittest.cc
index 179d27985fc36ce86c952df1f96b72f56976c440..0d4a5c803c18f4b84b6dab423e041cba76f253a2 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_header_extension_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_header_extension_unittest.cc
@@ -85,11 +85,15 @@ TEST(RtpHeaderExtensionTest, NonUniqueId) {
 
 TEST(RtpHeaderExtensionTest, GetTotalLength) {
   RtpHeaderExtensionMap map;
-  EXPECT_EQ(0u, map.GetTotalLengthInBytes());
+  constexpr RtpExtensionSize kExtensionSizes[] = {
+    {TransmissionOffset::kId, TransmissionOffset::kValueSizeBytes}
+  };
+  EXPECT_EQ(0u, map.GetTotalLengthInBytes(kExtensionSizes));
   EXPECT_TRUE(map.Register<TransmissionOffset>(3));
   static constexpr size_t kRtpOneByteHeaderLength = 4;
-  EXPECT_EQ(kRtpOneByteHeaderLength + (TransmissionOffset::kValueSizeBytes + 1),
-            map.GetTotalLengthInBytes());
+  EXPECT_EQ(
+      kRtpOneByteHeaderLength + (TransmissionOffset::kValueSizeBytes + 1),
+      map.GetTotalLengthInBytes(kExtensionSizes));
 }
 
 TEST(RtpHeaderExtensionTest, GetType) {