Add tests for H264 SVC support

The tests require H264 to be enabled using the proprietary_codecs
GN args.gn option.

Bug: webrtc:11607, webrtc:13961
Change-Id: I22dc3d94c844873ac12b9dce8e88a97f4fcf7657
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/276046
Commit-Queue: Florent Castelli <orphis@webrtc.org>
Reviewed-by: Philipp Hancke <phancke@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#38133}
diff --git a/pc/test/svc_e2e_tests.cc b/pc/test/svc_e2e_tests.cc
index 2bb6d6f..6948ab3 100644
--- a/pc/test/svc_e2e_tests.cc
+++ b/pc/test/svc_e2e_tests.cc
@@ -47,6 +47,7 @@
 using VideoCodecConfig = ::webrtc::webrtc_pc_e2e::
     PeerConnectionE2EQualityTestFixture::VideoCodecConfig;
 using ::cricket::kAv1CodecName;
+using ::cricket::kH264CodecName;
 using ::cricket::kVp8CodecName;
 using ::cricket::kVp9CodecName;
 using ::testing::Combine;
@@ -310,7 +311,22 @@
             Values(UseDependencyDescriptor::Disabled,
                    UseDependencyDescriptor::Enabled)),
     SvcTestNameGenerator);
-#if RTC_ENABLE_VP9
+
+#if defined(WEBRTC_USE_H264)
+INSTANTIATE_TEST_SUITE_P(
+    SvcTestH264,
+    SvcTest,
+    Combine(ValuesIn({
+                SvcTestParameters{kH264CodecName, "L1T1", 1, 1},
+                // SvcTestParameters{kH264CodecName, "L1T2", 1, 2},
+                // SvcTestParameters{kH264CodecName, "L1T3", 1, 3},
+            }),
+            Values(UseDependencyDescriptor::Disabled,
+                   UseDependencyDescriptor::Enabled)),
+    SvcTestNameGenerator);
+#endif
+
+#if defined(RTC_ENABLE_VP9)
 INSTANTIATE_TEST_SUITE_P(
     SvcTestVP9,
     SvcTest,