Check before send/receive rtp header extensions.

BUG=1788
R=pbos@webrtc.org, tommi@webrtc.org, wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/13949004

Patch from Changbin Shao <changbin.shao@intel.com>.

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@6744 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/config.h b/config.h
index 2e96ec1..e4bccf9 100644
--- a/config.h
+++ b/config.h
@@ -10,8 +10,8 @@
 
 // TODO(pbos): Move Config from common.h to here.
 
-#ifndef WEBRTC_VIDEO_ENGINE_NEW_INCLUDE_CONFIG_H_
-#define WEBRTC_VIDEO_ENGINE_NEW_INCLUDE_CONFIG_H_
+#ifndef WEBRTC_CONFIG_H_
+#define WEBRTC_CONFIG_H_
 
 #include <string>
 #include <vector>
@@ -73,9 +73,10 @@
 
 // RTP header extension to use for the video stream, see RFC 5285.
 struct RtpExtension {
-  RtpExtension(const char* name, int id) : name(name), id(id) {}
+  RtpExtension(const std::string& name, int id) : name(name), id(id) {}
   std::string ToString() const;
-  // TODO(mflodman) Add API to query supported extensions.
+  static bool IsSupported(const std::string& name);
+
   static const char* kTOffset;
   static const char* kAbsSendTime;
   std::string name;
@@ -109,4 +110,4 @@
 
 }  // namespace webrtc
 
-#endif  // WEBRTC_VIDEO_ENGINE_NEW_INCLUDE_CONFIG_H_
+#endif  // WEBRTC_CONFIG_H_