Add content type extension to capabilities

webrtc/media/engine/webrtcvideoengine2_unittest.cc

Index: webrtc/media/engine/webrtcvideoengine2_unittest.cc
diff --git a/webrtc/media/engine/webrtcvideoengine2_unittest.cc b/webrtc/media/engine/webrtcvideoengine2_unittest.cc
index 37e227f931dc26644aa04f022e1267c94659f679..41f1a2fe90cc215cd1cce1e12e06e2072c7e7546 100644
--- a/webrtc/media/engine/webrtcvideoengine2_unittest.cc
+++ b/webrtc/media/engine/webrtcvideoengine2_unittest.cc
@@ -273,6 +273,18 @@ TEST_F(WebRtcVideoEngine2Test, CVOSetHeaderExtensionBeforeCapturer) {
   EXPECT_TRUE(capturer.apply_rotation());
 }
 
+TEST_F(WebRtcVideoEngine2Test, SupportsVideoContentTypeHeaderExtension) {
+  RtpCapabilities capabilities = engine_.GetCapabilities();
+  ASSERT_FALSE(capabilities.header_extensions.empty());
+  for (const RtpExtension& extension : capabilities.header_extensions) {
+    if (extension.uri == RtpExtension::kVideoContentTypeUri) {
+      EXPECT_EQ(RtpExtension::kVideoContentTypeDefaultId, extension.id);
+      return;
+    }
+  }
+  FAIL() << "Video Content Type extension not in header-extension list.";
+}
+
 TEST_F(WebRtcVideoEngine2Test, CVOSetHeaderExtensionBeforeAddSendStream) {
   // Allocate the capturer first to prevent early destruction before channel's
   // dtor is called.