Pick the DTLS handshake timeout based on the ICE RTT estimate

webrtc/base/opensslstreamadapter.h

Index: webrtc/base/opensslstreamadapter.h
diff --git a/webrtc/base/opensslstreamadapter.h b/webrtc/base/opensslstreamadapter.h
index d3edf3a670f9ac8bfb3f2a4e918e3c44ba4bfa07..16b62eb3feb2d23b71ce5f103a379c225c76b036 100644
--- a/webrtc/base/opensslstreamadapter.h
+++ b/webrtc/base/opensslstreamadapter.h
@@ -76,6 +76,7 @@ class OpenSSLStreamAdapter : public SSLStreamAdapter {
   int StartSSL() override;
   void SetMode(SSLMode mode) override;
   void SetMaxProtocolVersion(SSLProtocolVersion version) override;
+  void SetInitialRetransmissionTimeout(int timeout_ms) override;
 
   StreamResult Read(void* data,
                     size_t data_len,
@@ -212,6 +213,10 @@ class OpenSSLStreamAdapter : public SSLStreamAdapter {
 
   // Max. allowed protocol version
   SSLProtocolVersion ssl_max_version_;
+
+  // A 50-ms initial timeout ensures rapid setup on fast connections, but may
+  // be too aggressive for low bandwidth links.
+  int dtls_handshake_timeout_ms_ = 50;
 };
 
 /////////////////////////////////////////////////////////////////////////////