Switch DesktopEnvironment to return a DesktopCapturer.

remoting/test/protocol_perftest.cc

Index: remoting/test/protocol_perftest.cc
diff --git a/remoting/test/protocol_perftest.cc b/remoting/test/protocol_perftest.cc
index 1e1c14aaa29ed6f988ee38fb37038a575454fc5a..438cbb89821a6d1ff31752d15032cfad2c6da6b3 100644
--- a/remoting/test/protocol_perftest.cc
+++ b/remoting/test/protocol_perftest.cc
@@ -348,7 +348,7 @@ class IntermittentChangeFrameGenerator
       : frame_index_(0) {}
 
   scoped_ptr<webrtc::DesktopFrame> GenerateFrame(
-      webrtc::ScreenCapturer::Callback* callback) {
+      webrtc::DesktopCapturer::Callback* callback) {
     const int kWidth = 800;
     const int kHeight = 600;