Add option to enable ECDSA key for Java API.

talk/app/webrtc/java/jni/peerconnection_jni.cc

Index: talk/app/webrtc/java/jni/peerconnection_jni.cc
diff --git a/talk/app/webrtc/java/jni/peerconnection_jni.cc b/talk/app/webrtc/java/jni/peerconnection_jni.cc
index c326ccff6bede1e3e93e5605be72be86a672df7d..654e5a01e2c5bffb6846aa20e984d6923095a98b 100644
--- a/talk/app/webrtc/java/jni/peerconnection_jni.cc
+++ b/talk/app/webrtc/java/jni/peerconnection_jni.cc
@@ -93,6 +93,7 @@ using rtc::Bind;
 using rtc::Thread;
 using rtc::ThreadManager;
 using rtc::scoped_ptr;
+using rtc::scoped_refptr;
 using webrtc::AudioSourceInterface;
 using webrtc::AudioTrackInterface;
 using webrtc::AudioTrackVector;
@@ -125,6 +126,9 @@ namespace webrtc_jni {
 // Field trials initialization string
 static char *field_trials_init_string = NULL;
 
+// ECSDA certificate
+static scoped_refptr<rtc::RTCCertificate> g_rtc_certificate;
+
 #if defined(ANDROID) && !defined(WEBRTC_CHROMIUM_BUILD)
 // Set in PeerConnectionFactory_initializeAndroidGlobals().
 static bool factory_static_initialized = false;
@@ -132,6 +136,7 @@ static bool vp8_hw_acceleration_enabled = true;
 #endif
 
 extern "C" jint JNIEXPORT JNICALL JNI_OnLoad(JavaVM *jvm, void *reserved) {
+  LOG(LS_INFO) << "JNI_OnLoad";
   jint ret = InitGlobalJniVariables(jvm);
   if (ret < 0)
     return -1;
@@ -139,6 +144,15 @@ extern "C" jint JNIEXPORT JNICALL JNI_OnLoad(JavaVM *jvm, void *reserved) {
   CHECK(rtc::InitializeSSL()) << "Failed to InitializeSSL()";
   LoadGlobalClassReferenceHolder();
 
+  scoped_ptr<rtc::SSLIdentity> ssl_identity(
+      rtc::SSLIdentity::Generate(std::string(), rtc::KT_ECDSA));
+  if (ssl_identity.get()) {
+    g_rtc_certificate = rtc::RTCCertificate::Create(ssl_identity.Pass());

[jiayl2, 2015/08/25 23:06:02]

If the app runs for days or months, the certificate may expire, assuming this
method is called on per app launch?

Also, there is the privacy side that some app may not want to reuse the
certificate across PeerConnection.

I think it'll be better to create a new certificate in createPeerConnection.

[AlexG, 2015/08/25 23:15:26]

ok. Should I call both rtc::SSLIdentity::Generate() and
rtc::RTCCertificate::Create() in createPeerConnection or SSLIdentity can be
generated in JNI_OnLoad()?

[AlexG, 2015/08/25 23:56:02]

Done.

+    LOG(LS_INFO) << "ECDSA certificate created.";
+  } else {
+    LOG(LS_WARNING) << "Failed to generate SSLIdentity.";
+  }
+
   return ret;
 }
 
@@ -1340,6 +1354,8 @@ JOW(jlong, PeerConnectionFactory_nativeCreatePeerConnection)(
       GetIntField(jni, j_rtc_config, j_audio_jitter_buffer_max_packets_id);
   rtc_config.audio_jitter_buffer_fast_accelerate = GetBooleanField(
       jni, j_rtc_config, j_audio_jitter_buffer_fast_accelerate_id);
+  if (g_rtc_certificate.get() != NULL)
+    rtc_config.certificates.push_back(g_rtc_certificate);
 
   PCOJava* observer = reinterpret_cast<PCOJava*>(observer_p);
   observer->SetConstraints(new ConstraintsWrapper(jni, j_constraints));