Fix wrong OS guard in DelegatedFrameHost

Bug: 900373
Change-Id: Ibaaeda2fcff69b5bf45eb7de767731bf53177f56
Reviewed-on: https://chromium-review.googlesource.com/c/1336510Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Commit-Queue: Saman Sami <samans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608198}

content/browser/renderer_host/delegated_frame_host.cc

@@ -52,7 +52,7 @@ DelegatedFrameHost::DelegatedFrameHost(const viz::FrameSinkId& frame_sink_id,
   DCHECK(host_frame_sink_manager_);
   viz::ReportFirstSurfaceActivation should_report_first_surface_activation =
       viz::ReportFirstSurfaceActivation::kNo;
-#ifdef CHROME_OS
+#ifdef OS_CHROMEOS
   should_report_first_surface_activation =
       viz::ReportFirstSurfaceActivation::kYes;
 #endif