Create the API that returns the RTCConfiguration of the PeerConnection.

third_party/WebKit/Source/web/tests/ActiveConnectionThrottlingTest.cpp

Index: third_party/WebKit/Source/web/tests/ActiveConnectionThrottlingTest.cpp
diff --git a/third_party/WebKit/Source/web/tests/ActiveConnectionThrottlingTest.cpp b/third_party/WebKit/Source/web/tests/ActiveConnectionThrottlingTest.cpp
index 1733f3b17dbd792b377320bcec103fa29fe0b09d..2721fb168d21108090fd651eea82a28be1729351 100644
--- a/third_party/WebKit/Source/web/tests/ActiveConnectionThrottlingTest.cpp
+++ b/third_party/WebKit/Source/web/tests/ActiveConnectionThrottlingTest.cpp
@@ -3,6 +3,7 @@
 // found in LICENSE file.
 
 #include "platform/testing/TestingPlatformSupport.h"
+#include "public/platform/WebRTCConfiguration.h"
 #include "public/platform/WebRTCError.h"
 #include "public/platform/WebRTCPeerConnectionHandler.h"
 #include "public/platform/WebRTCSessionDescription.h"
@@ -72,6 +73,9 @@ class MockWebRTCPeerConnectionHandler : public WebRTCPeerConnectionHandler {
   WebRTCErrorType setConfiguration(const WebRTCConfiguration&) override {
     return WebRTCErrorType::kNone;
   }
+  blink::WebRTCConfiguration getConfiguration() override {
+    return blink::WebRTCConfiguration();
+  }
   bool addStream(const WebMediaStream&, const WebMediaConstraints&) override {
     return true;
   }