[Cleanup] Remove the obsolete Prerender field trial.

chrome/browser/android/chrome_startup_flags.cc

Index: chrome/browser/android/chrome_startup_flags.cc
diff --git a/chrome/browser/android/chrome_startup_flags.cc b/chrome/browser/android/chrome_startup_flags.cc
index 83b46648605df7cbbb93ee11082ec53c49887528..ed0dfb3f6c6ee0d1719615d7be2809489cf46e11 100644
--- a/chrome/browser/android/chrome_startup_flags.cc
+++ b/chrome/browser/android/chrome_startup_flags.cc
@@ -35,10 +35,6 @@ void SetCommandLineSwitchASCII(const std::string& switch_string,
 }  // namespace
 
 void SetChromeSpecificCommandLineFlags() {
-  // Enable prerender with holdback.
-  SetCommandLineSwitchASCII(switches::kPrerenderMode,
-                            switches::kPrerenderModeSwitchValueAuto);
-
   // Enable prerender for the omnibox.
   SetCommandLineSwitchASCII(switches::kPrerenderFromOmnibox,
                             switches::kPrerenderFromOmniboxSwitchValueEnabled);