[Chromoting] Implement new APIs in DesktopCapturer

remoting/host/desktop_capturer_proxy.h

Index: remoting/host/desktop_capturer_proxy.h
diff --git a/remoting/host/desktop_capturer_proxy.h b/remoting/host/desktop_capturer_proxy.h
index 1a680a3f96de4f9e056fd2c40f900aa26620ea53..8dc7ca24fa46b5d8c3bd989d3dd4d597f8e4a356 100644
--- a/remoting/host/desktop_capturer_proxy.h
+++ b/remoting/host/desktop_capturer_proxy.h
@@ -29,6 +29,8 @@ class CursorShapeInfo;
 
 // DesktopCapturerProxy is responsible for calling webrtc::DesktopCapturer on
 // the capturer thread and then returning results to the caller's thread.
+// GetSourceList() and SelectSource() functions are not implemented by this
+// class, they always return false.
 class DesktopCapturerProxy : public webrtc::DesktopCapturer {
  public:
   explicit DesktopCapturerProxy(
@@ -46,6 +48,8 @@ class DesktopCapturerProxy : public webrtc::DesktopCapturer {
   void SetSharedMemoryFactory(std::unique_ptr<webrtc::SharedMemoryFactory>
                                   shared_memory_factory) override;
   void CaptureFrame() override;
+  bool GetSourceList(SourceList* sources) override;
+  bool SelectSource(SourceId id) override;
 
  private:
   class Core;