Add support for GCM cipher suites from RFC 7714.

talk/app/webrtc/peerconnectionfactory.cc

Index: talk/app/webrtc/peerconnectionfactory.cc
diff --git a/talk/app/webrtc/peerconnectionfactory.cc b/talk/app/webrtc/peerconnectionfactory.cc
index 672355085a6b775e57264dd92a241f64295260e3..2441cd6053b9195058fe4354bcf8288a424e8a80 100644
--- a/talk/app/webrtc/peerconnectionfactory.cc
+++ b/talk/app/webrtc/peerconnectionfactory.cc
@@ -201,6 +201,7 @@ bool PeerConnectionFactory::Initialize() {
       new cricket::ChannelManager(media_engine, worker_thread_));
 
   channel_manager_->SetVideoRtxEnabled(true);
+  channel_manager_->SetEnableGcmCryptoSuites(options_.enable_gcm_crypto_suites);
   if (!channel_manager_->Init()) {
     return false;
   }
@@ -211,6 +212,14 @@ bool PeerConnectionFactory::Initialize() {
   return true;
 }
 
+void PeerConnectionFactory::SetOptions(const Options& options) {
+  options_ = options;
+  if (channel_manager_) {
+    channel_manager_->SetEnableGcmCryptoSuites(
+        options.enable_gcm_crypto_suites);
+  }
+}
+
 rtc::scoped_refptr<AudioSourceInterface>
 PeerConnectionFactory::CreateAudioSource(
     const MediaConstraintsInterface* constraints) {