Fix compilation if HAVE_WEBRTC_VIDEO is not defined.

talk/media/webrtc/webrtcvideocapturer_unittest.cc

Index: talk/media/webrtc/webrtcvideocapturer_unittest.cc
diff --git a/talk/media/webrtc/webrtcvideocapturer_unittest.cc b/talk/media/webrtc/webrtcvideocapturer_unittest.cc
index 85db32e7d242e46910505d8919eab751258eee77..99eb7f249cec6eac7060ef6f9178691689add601 100644
--- a/talk/media/webrtc/webrtcvideocapturer_unittest.cc
+++ b/talk/media/webrtc/webrtcvideocapturer_unittest.cc
@@ -25,6 +25,8 @@
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#ifdef HAVE_WEBRTC_VIDEO
+
 #include <stdio.h>
 #include <vector>
 #include "talk/media/base/testutils.h"
@@ -146,3 +148,5 @@ TEST_F(WebRtcVideoCapturerTest, TestCaptureWithoutInit) {
   EXPECT_TRUE(capturer_->GetCaptureFormat() == NULL);
   EXPECT_FALSE(capturer_->IsRunning());
 }
+
+#endif  // HAVE_WEBRTC_VIDEO