[Prerender] Get the prerender mode from Finch field trial.

chrome/browser/chrome_browser_field_trials_mobile.cc

Index: chrome/browser/chrome_browser_field_trials_mobile.cc
diff --git a/chrome/browser/chrome_browser_field_trials_mobile.cc b/chrome/browser/chrome_browser_field_trials_mobile.cc
index 1793b688aad0a7c989153aa58b459f16f3ae45d8..8bdcb7c6dbd42310cf027629126fa76c9114525d 100644
--- a/chrome/browser/chrome_browser_field_trials_mobile.cc
+++ b/chrome/browser/chrome_browser_field_trials_mobile.cc
@@ -17,9 +17,9 @@
 
 namespace chrome {
 
-void SetupMobileFieldTrials(const base::CommandLine& parsed_command_line) {
+void SetupMobileFieldTrials() {
 #if defined(OS_ANDROID)
-  prerender::ConfigurePrerender(parsed_command_line);
+  prerender::ConfigurePrerender();
 
   // Force-enable profiler timing depending on the field trial.
   if (base::FieldTrialList::FindFullName("ProfilerTiming") == "Enable")