[Chromoting] Implement new APIs in DesktopCapturer

remoting/protocol/connection_unittest.cc

Index: remoting/protocol/connection_unittest.cc
diff --git a/remoting/protocol/connection_unittest.cc b/remoting/protocol/connection_unittest.cc
index fc063183273b2b0af4515cf87926cffe7820d3db..1217aea7b3673ad11c6a521940ccbc90c54372b8 100644
--- a/remoting/protocol/connection_unittest.cc
+++ b/remoting/protocol/connection_unittest.cc
@@ -94,6 +94,14 @@ class TestScreenCapturer : public webrtc::DesktopCapturer {
                                std::move(frame));
   }
 
+  bool GetSourceList(SourceList* sources) override {
+    return true;
+  }
+
+  bool SelectSource(SourceId id) override {
+    return true;
+  }
+
  private:
   Callback* callback_ = nullptr;
   bool first_frame_sent_ = false;