Adding support for Unified Plan offer/answer negotiation.

webrtc/p2p/base/sessiondescription.cc

Index: webrtc/p2p/base/sessiondescription.cc
diff --git a/webrtc/p2p/base/sessiondescription.cc b/webrtc/p2p/base/sessiondescription.cc
index 1e69c83e76243da6d0864025624435a2e12d2d01..c0f190692c1975947545023fe268efb44f378f34 100644
--- a/webrtc/p2p/base/sessiondescription.cc
+++ b/webrtc/p2p/base/sessiondescription.cc
@@ -122,14 +122,18 @@ const ContentInfo* SessionDescription::FirstContent() const {
 void SessionDescription::AddContent(const std::string& name,
                                     const std::string& type,
                                     ContentDescription* description) {
-  contents_.push_back(ContentInfo(name, type, description));
+  ContentInfo content_info(name, type, description);
+  content_info.msection_index = contents_.size();
+  contents_.push_back(content_info);
 }
 
 void SessionDescription::AddContent(const std::string& name,
                                     const std::string& type,
                                     bool rejected,
                                     ContentDescription* description) {
-  contents_.push_back(ContentInfo(name, type, rejected, description));
+  ContentInfo content_info(name, type, rejected, description);
+  content_info.msection_index = contents_.size();
+  contents_.push_back(content_info);
 }
 
 void SessionDescription::AddContent(const std::string& name,
@@ -137,8 +141,9 @@ void SessionDescription::AddContent(const std::string& name,
                                     bool rejected,
                                     bool bundle_only,
                                     ContentDescription* description) {
-  contents_.push_back(
-      ContentInfo(name, type, rejected, bundle_only, description));
+  ContentInfo content_info(name, type, rejected, bundle_only, description);
+  content_info.msection_index = contents_.size();
+  contents_.push_back(content_info);
 }
 
 bool SessionDescription::RemoveContentByName(const std::string& name) {