Prerender: Remove deprecated prerender experiment histograms.

chrome/browser/prerender/prerender_manager.cc

Index: chrome/browser/prerender/prerender_manager.cc
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index f97d9cef68fe32ccad83161c5424530b0f6eaf48..431d6c210da0d208fbd20c5f507861afffbc7094 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -561,32 +561,6 @@ void PrerenderManager::SetMode(PrerenderManagerMode mode) {
 }
 
 // static
-const char* PrerenderManager::GetModeString() {
-  switch (mode_) {
-    case PRERENDER_MODE_DISABLED:
-      return "_Disabled";
-    case PRERENDER_MODE_ENABLED:
-    case PRERENDER_MODE_EXPERIMENT_PRERENDER_GROUP:
-      return "_Enabled";
-    case PRERENDER_MODE_EXPERIMENT_CONTROL_GROUP:
-      return "_Control";
-    case PRERENDER_MODE_EXPERIMENT_MULTI_PRERENDER_GROUP:
-      return "_Multi";
-    case PRERENDER_MODE_EXPERIMENT_15MIN_TTL_GROUP:
-      return "_15MinTTL";
-    case PRERENDER_MODE_EXPERIMENT_NO_USE_GROUP:
-      return "_NoUse";
-    case PRERENDER_MODE_NOSTATE_PREFETCH:
-      return "_NoStatePrefetch";
-    case PRERENDER_MODE_MAX:
-    default:
-      NOTREACHED() << "Invalid PrerenderManager mode.";
-      break;
-  }
-  return "";
-}
-
-// static
 bool PrerenderManager::IsPrerenderingPossible() {
   return GetMode() != PRERENDER_MODE_DISABLED;
 }