[Chromoting] Use HostExperimentSessionPlugin in host

remoting/host/desktop_environment_options.cc

Index: remoting/host/desktop_environment_options.cc
diff --git a/remoting/host/desktop_environment_options.cc b/remoting/host/desktop_environment_options.cc
index ec1995e12d1753de296cd04983555975bf902c65..0e15351c01aedf5c6a72308f455933fa49497683 100644
--- a/remoting/host/desktop_environment_options.cc
+++ b/remoting/host/desktop_environment_options.cc
@@ -4,8 +4,11 @@
 
 #include "remoting/host/desktop_environment_options.h"
 
+#include <string>
 #include <utility>
 
+#include "base/optional.h"
+
 namespace remoting {
 
 using DesktopCaptureOptions = webrtc::DesktopCaptureOptions;
@@ -68,4 +71,23 @@ void DesktopEnvironmentOptions::set_enable_user_interface(bool enabled) {
   enable_user_interface_ = enabled;
 }
 
+void DesktopEnvironmentOptions::ApplyHostSessionOptions(
+    const HostSessionOptions& options) {
+#if defined(OS_WIN)
+  base::Optional<std::string> directx_capturer =
+      options.Get("DirectX-Capturer");
+  if (directx_capturer) {
+    desktop_capture_options_.set_allow_directx_capturer(
+        *directx_capturer == "true");
+  }
+#endif
+  // This field is for test purpose. Usually it should not be set to false.
+  base::Optional<std::string> detect_updated_region =
+      options.Get("Detect-Updated-Region");
+  if (detect_updated_region) {
+    desktop_capture_options_.set_detect_updated_region(
+        *detect_updated_region == "true");
+  }
+}
+
 }  // namespace remoting