Make prefetch default on (subject to the regular predictive networking preference).

chrome/browser/prefetch/prefetch_field_trial.cc

Index: chrome/browser/prefetch/prefetch_field_trial.cc
diff --git a/chrome/browser/prefetch/prefetch_field_trial.cc b/chrome/browser/prefetch/prefetch_field_trial.cc
index 0db983bc26c029354597d66980cc0bae522cc8cc..abdb11215ec4476d86865815ddeef52388430774 100644
--- a/chrome/browser/prefetch/prefetch_field_trial.cc
+++ b/chrome/browser/prefetch/prefetch_field_trial.cc
@@ -12,15 +12,9 @@
 
 namespace prefetch {
 
-bool IsPrefetchFieldTrialEnabled() {
+bool DisableForFieldTrial() {
   std::string experiment = base::FieldTrialList::FindFullName("Prefetch");
-  if (StartsWithASCII(experiment, "ExperimentYes", false))
-    return true;
-  // If this client needs to prefetch for the Prerender Local Predictor,
-  // enable prefetching.
-  if (prerender::IsLocalPredictorPrerenderPrefetchEnabled())
-    return true;
-  return false;
+  return StartsWithASCII(experiment, "ExperimentDisable", false);
 }
 
 }  // namespace prefetch