Add a telemetry measurement for property tree performance.

content/browser/renderer_host/render_process_host_impl.cc

Index: content/browser/renderer_host/render_process_host_impl.cc
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index 8303929558f815a15262872e37998fed0ce7c21c..f85a72992c4ece163c1aa8e35d0fdc6541df265e 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -1070,6 +1070,9 @@ static void AppendCompositorCommandLineFlags(base::CommandLine* command_line) {
   if (IsPinchVirtualViewportEnabled())
     command_line->AppendSwitch(cc::switches::kEnablePinchVirtualViewport);
 
+  if (IsPropertyTreeVerificationEnabled())
+    command_line->AppendSwitch(cc::switches::kEnablePropertyTreeVerification);
+
   if (IsDelegatedRendererEnabled())
     command_line->AppendSwitch(switches::kEnableDelegatedRenderer);